The interpretation timeline
Genesis 1:6 Douay-Rheims

And God said: Let there be a firmament made amidst the waters: and let it divide the waters from the waters.

A.D. 220 – 1875 15 witnesses 18 excerpts

Patristic

before A.D. 750
220
A.D.
Tertullian Patristic
c. A.D. 150–220
“What of the fact that waters were in some way the regulating powers by which the disposition of the world thenceforward was constituted by God? For the suspension of the celestial firmament in the midst He caused by "dividing the waters;" the suspension of "the dry land" He accomplished by "separating the waters." After the world had been hereupon set in order through its elements, when inhabitants were given it, "the waters" were the first to receive the precept "to bring forth living creatures." Water was the first to produce that which had life, that it might be no wonder in baptism if waters know how to give life. For was not the work of fashioning man himself also achieved with the aid of waters? Suitable material is found in the earth, yet not apt for the purpose unless it be moist and juicy; which (earth) "the waters," separated the fourth day before into their own place, temper with their remaining moisture to a clayey consistency.”
Source
235
A.D.
Hippolytus of Rome Patristic
c. A.D. 170–235
“On the first day God made what He made out of nothing. But on the other days He did not make out of nothing, but out of what He had made on the first day, by moulding it according to His pleasure.”
“And let it divide between water and water: and it was so. And God made the firmament; and God divided between the water which was under the firmament, and the water above the firmament: and it was so. As the excessive volume of water bore along over the face of the earth, the earth was by reason thereof "invisible" and "formless." When the Lord of all designed to make the invisible visible, He fixed then a third part of the waters in the midst; and another third part He set by itself on high, raising it together with the firmament by His own power; and the remaining third He left beneath, for the use and benefit of men. Now at this point we have an asterisk. The words are found in the Hebrew, but do not occur in the Septuagint.”
Source
379
A.D.
Basil of Caesarea Patristic
c. A.D. 330–379
“1. We have now recounted the works of the first day, or rather of one day. Far be it from me indeed, to take from it the privilege it enjoys of having been for the Creator a day apart, a day which is not counted in the same order as the others. Our discussion yesterday treated of the works of this day, and divided the narrative so as to give you food for your souls in the morning, and joy in the evening. Today we pass on to the wonders of the second day. And here I do not wish to speak of the narrator's talent, but of the grace of Scripture, for the narrative is so naturally told that it pleases and delights all the friends of truth. It is this charm of truth which the Psalmist expresses so emphatically when he says, How sweet are your words unto my taste, yea, sweeter than honey to my mouth. Yesterday then, as far as we were able, we delighted our souls by conversing about the oracles of God, and now today we are met together again on the second day to contemplate the wonders of the second day. I know that many artisans, belonging to mechanical trades, are crowding around me. A day's labour hardly suffices to maintain them; therefore I am compelled to abridge my discourse, so as not to keep them too long from their work. What shall I say to them? The time which you lend to God is not lost: he will return it to you with large interest. Whatever difficulties may trouble you the Lord will disperse them. To those who have preferred spiritual welfare, He will give health of body, keenness of mind, success in business, and unbroken prosperity. And, even if in this life our efforts should not realise our hopes, the teachings of the Holy Spirit are none the less a rich treasure for the ages to come. Deliver your heart, then, from the cares of this life and give close heed to my words. Of what avail will it be to you if you are here in the body, and your heart is anxious about your earthly treasure? 2. And God said Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. Genesis 1:6 Yesterday we heard God's decree, Let there be light. Today it is, Let there be a firmament. There appears to be something more in this. The word is not limited to a simple command. It lays down the reason necessitating the structure of the firmament: it is, it is said, to separate the waters from the waters. And first let us ask how God speaks? Is it in our manner? Does His intelligence receive an impression from objects, and, after having conceived them, make them known by particular signs appropriate to each of them? Has He consequently recourse to the organs of voice to convey His thoughts? Is He obliged to strike the air by the articulate movements of the voice, to unveil the thought hidden in His heart? Would it not seem like an idle fable to say that God should need such a circuitous method to manifest His thoughts? And is it not more conformable with true religion to say, that the divine will and the first impetus of divine intelligence are the Word of God? It is He whom Scripture vaguely represents, to show us that God has not only wished to create the world, but to create it with the help of a co-operator. Scripture might continue the history as it is begun: In the beginning God created the heaven and the earth; afterwards He created light, then He created the firmament. But, by making God command and speak, the Scripture tacitly shows us Him to Whom this order and these words are addressed. It is not that it grudges us the knowledge of the truth, but that it may kindle our desire by showing us some trace and indication of the mystery. We seize with delight, and carefully keep, the fruit of laborious efforts, while a possession easily attained is despised. Such is the road and the course which Scripture follows to lead us to the idea of the Only begotten. And certainly, God's immaterial nature had no need of the material language of voice, since His very thoughts could be transmitted to His fellow-worker. What need then of speech, for those Who by thought alone could communicate their counsels to each other? Voice was made for hearing, and hearing for voice. Where there is neither air, nor tongue, nor ear, nor that winding canal which carries sounds to the seat of sensation in the head, there is no need for words: thoughts of the soul are sufficient to transmit the will. As I said then, this language is only a wise and ingenious contrivance to set our minds seeking the Person to whom the words are addressed. 3. In the second place, does the firmament that is called heaven differ from the firmament that God made in the beginning? Are there two heavens? The philosophers, who discuss heaven, would rather lose their tongues than grant this. There is only one heaven, they pretend; and it is of a nature neither to admit of a second, nor of a third, nor of several others. The essence of the celestial body quite complete constitutes its vast unity. Because, they say, every body which has a circular motion is one and finite. And if this body is used in the construction of the first heaven, there will be nothing left for the creation of a second or a third. Here we see what those imagine who put under the Creator's hand uncreated matter; a lie that follows from the first fable. But we ask the Greek sages not to mock us before they are agreed among themselves. Because there are among them some who say there are infinite heavens and worlds. When grave demonstrations shall have upset their foolish system, when the laws of geometry shall have established that, according to the nature of heaven, it is impossible that there should be two, we shall only laugh the more at this elaborate scientific trifling. These learned men see not merely one bubble but several bubbles formed by the same cause, and they doubt the power of creative wisdom to bring several heavens into being! We find, however, if we raise our eyes towards the omnipotence of God, that the strength and grandeur of the heavens differ from the drops of water bubbling on the surface of a fountain. How ridiculous, then, is their argument of impossibility! As for myself, far from not believing in a second, I seek for the third whereon the blessed Paul was found worthy to gaze. And does not the Psalmist in saying heaven of heavens give us an idea of their plurality? Is the plurality of heaven stranger than the seven circles through which nearly all the philosophers agree that the seven planets pass—circles which they represent to us as placed in connection with each other like casks fitting the one into the other? These circles, they say, carried away in a direction contrary to that of the world, and striking the æther, make sweet and harmonious sounds, unequalled by the sweetest melody. And if we ask them for the witness of the senses, what do they say? That we, accustomed to this noise from our birth, on account of hearing it always, have lost the sense of it; like men in smithies with their ears incessantly dinned. If I refuted this ingenious frivolity, the untruth of which is evident from the first word, it would seem as though I did not know the value of time, and mistrusted the intelligence of such an audience. But let me leave the vanity of outsiders to those who are without, and return to the theme proper to the Church. If we believe some of those who have preceded us, we have not here the creation of a new heaven, but a new account of the first. The reason they give is, that the earlier narrative briefly described the creation of heaven and earth; while here scripture relates in greater detail the manner in which each was created. I, however, since Scripture gives to this second heaven another name and its own function, maintain that it is different from the heaven which was made at the beginning; that it is of a stronger nature and of a special use to the universe. The mass of waters, which from all directions flowed over the earth, and was suspended in the air, was infinite, so that there was no proportion between it and the other elements. Thus, as it has been already said, the abyss covered the earth. We give the reason for this abundance of water. None of you assuredly will attack our opinion; not even those who have the most cultivated minds, and whose piercing eye can penetrate this perishable and fleeting nature; you will not accuse me of advancing impossible or imaginary theories, nor will you ask me upon what foundation the fluid element rests. By the same reason which makes them attract the earth, heavier than water, from the extremities of the world to suspend it in the centre, they will grant us without doubt that it is due both to its natural attraction downwards and its general equilibrium, that this immense quantity of water rests motionless upon the earth. Therefore the prodigious mass of waters was spread around the earth; not in proportion with it and infinitely larger, thanks to the foresight of the supreme Artificer, Who, from the beginning, foresaw what was to come, and at the first provided all for the future needs of the world. But what need was there for this superabundance of water? The essence of fire is necessary for the world, not only in the economy of earthly produce, but for the completion of the universe; for it would be imperfect if the most powerful and the most vital of its elements were lacking. Now fire and water are hostile to and destructive of each other. Fire, if it is the stronger, destroys water, and water, if in greater abundance, destroys fire. As, therefore, it was necessary to avoid an open struggle between these elements, so as not to bring about the dissolution of the universe by the total disappearance of one or the other, the sovereign Disposer created such a quantity of water that in spite of constant diminution from the effects of fire, it could last until the time fixed for the destruction of the world. He who planned all with weight and measure, He who, according to the word of Job, knows the number of the drops of rain, knew how long His work would last, and for how much consumption of fire He ought to allow. This is the reason of the abundance of water at the creation. Further, there is no one so strange to life as to need to learn the reason why fire is essential to the world. Not only all the arts which support life, the art of weaving, that of shoemaking, of architecture, of agriculture, have need of the help of fire, but the vegetation of trees, the ripening of fruits, the breeding of land and water animals, and their nourishment, all existed from heat from the beginning, and have been since maintained by the action of heat. The creation of heat was then indispensable for the formation and the preservation of beings, and the abundance of waters was no less so in the presence of the constant and inevitable consumption by fire. 6. Survey creation; you will see the power of heat reigning over all that is born and perishes. On account of it comes all the water spread over the earth, as well as that which is beyond our sight and is dispersed in the depths of the earth. On account of it are abundance of fountains, springs or wells, courses of rivers, both mountain torrents and ever flowing streams, for the storing of moisture in many and various reservoirs. From the East, from the winter solstice flows the Indus, the greatest river of the earth, according to geographers. From the middle of the East proceed the Bactrus, the Choaspes, and the Araxes, from which the Tanais detaches itself to fall into the Palus-Mæotis. Add to these the Phasis which descends from Mount Caucasus, and countless other rivers, which, from northern regions, flow into the Euxine Sea. From the warm countries of the West, from the foot of the Pyrenees, arise the Tartessus and the Ister, of which the one discharges itself into the sea beyond the Pillars and the other, after flowing through Europe, falls into Euxine Sea. Is there any need to enumerate those which the Ripæan mountains pour forth in the heart of Scythia, the Rhone, and so many other rivers, all navigable, which after having watered the countries of the western Gauls and of Celts and of the neighbouring barbarians, flow into the Western sea? And others from the higher regions of the South flow through Ethiopia, to discharge themselves some into our sea, others into inaccessible seas, the Ægon the Nyses, the Chremetes, and above all the Nile, which is not of the character of a river when, like a sea, it inundates Egypt. Thus the habitable part of our earth is surrounded by water, linked together by vast seas and irrigated by countless perennial rivers, thanks to the ineffable wisdom of Him Who ordered all to prevent this rival element to fire from being entirely destroyed. However, a time will come, when all shall be consumed by fire; as Isaiah says of the God of the universe in these words, That says to the deep, Be dry, and I will dry up your rivers. Isaiah 44:27 Reject then the foolish wisdom of this world, and receive with me the more simple but infallible doctrine of truth. 7. Therefore we read: Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. I have said what the word firmament in Scripture means. It is not in reality a firm and solid substance which has weight and resistance; this name would otherwise have better suited the earth. But, as the substance of superincumbent bodies is light, without consistency, and cannot be grasped by any one of our senses, it is in comparison with these pure and imperceptible substances that the firmament has received its name. Imagine a place fit to divide the moisture, sending it, if pure and filtered, into higher regions, and making it fall, if it is dense and earthy; to the end that by the gradual withdrawal of the moist particles the same temperature may be preserved from the beginning to the end. You do not believe in this prodigious quantity of water; but you do not take into account the prodigious quantity of heat, less considerable no doubt in bulk, but exceedingly powerful nevertheless, if you consider it as destructive of moisture. It attracts surrounding moisture, as the melon shows us, and consumes it as quickly when attracted, as the flame of the lamp draws to it the fuel supplied by the wick and burns it up. Who doubts that the æther is an ardent fire? If an impassable limit had not been assigned to it by the Creator, what would prevent it from setting on fire and consuming all that is near it, and absorbing all the moisture from existing things? The aerial waters which veil the heavens with vapours that are sent forth by rivers, fountains, marshes, lakes, and seas, prevent the æther from invading and burning up the universe. Thus we see even this sun, in the summer season, dry up in a moment a damp and marshy country, and make it perfectly arid. What has become of all the water? Let these masters of omniscience tell us. Is it not plain to every one that it has risen in vapour, and has been consumed by the heat of the sun? They say, none the less, that even the sun is without heat. What time they lose in words! And see what proof they lean upon to resist what is perfectly plain. Its colour is white, and neither reddish nor yellow. It is not then fiery by nature, and its heat results, they say, from the velocity of its rotation. What do they gain? That the sun does not seem to absorb moisture? I do not, however, reject this statement, although it is false, because it helps my argument. I said that the consumption of heat required this prodigious quantity of water. That the sun owes its heat to its nature, or that heat results from its action, makes no difference, provided that it produces the same effects upon the same matter. If you kindle fire by rubbing two pieces of wood together, or if you light them by holding them to a flame, you will have absolutely the same effect. Besides, we see that the great wisdom of Him who governs all, makes the sun travel from one region to another, for fear that, if it remained always in the same place, its excessive heat would destroy the order of the universe. Now it passes into southern regions about the time of the winter solstice, now it returns to the sign of the equinox; from thence it betakes itself to northern regions during the summer solstice, and keeps up by this imperceptible passage a pleasant temperature throughout all the world. Let the learned people see if they do not disagree among themselves. The water which the sun consumes is, they say, what prevents the sea from rising and flooding the rivers; the warmth of the sun leaves behind the salts and the bitterness of the waters, and absorbs from them the pure and drinkable particles, thanks to the singular virtue of this planet in attracting all that is light and in allowing to fall, like mud and sediment, all which is thick and earthy. From thence come the bitterness, the salt taste and the power of withering and drying up which are characteristic of the sea. While as is notorious, they hold these views, they shift their ground and say that moisture cannot be lessened by the sun.”
“And surely we need not believe, because [the firmament] seems to have had its origin, according to the general understanding, from water, that it is like either frozen water or some such material that takes its origin from the percolation of moisture, such as is a crystalline rock.”
386
A.D.
Cyril of Jerusalem Patristic
A.D. 313–386
“For what fault have they to find with the vast creation of God, who out of the fluid nature of the waters formed the stable substance of the heavens? For God said, "Let there be a firmament in the midst of the waters." God spoke once for all, and it stands fast, never failing.”
date
unknown
c. A.D. 550
“On the second day God said: Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. He made this heaven, not the one above, but the visible heaven which he crystallised from the waters like ice. But I shall endeavour to place the matter before your eyes, for many things are better explained by ocular than by oral demonstration. This water, let us suppose, overflowed the earth five cubits. Then God said: Let there be a firmament in the midst of the water, and thereupon a solid ice-like substance was produced in the midst of the waters, which made lighter the upper half of the water, and left the other half underneath, as it is written: Let there be a firmament in the midst of the water, and let it make a division between the waters. But wherefore does he call it the firmament? It is, because God made it firm and solid from waters which are of rarer and less compact substance. Wherefore David also says: Praise him in the firmament of his power; and, to take another example, we may adduce smoke, which when emitted from burning wood is rarified and attenuated, but when it mounts up high into the air becomes transformed into the density of a cloud. In this wise, when God had made the waters, which are by nature rarified, ascend on high, He there made them solid. And that this example is to the point, and true, Isaiah testifies where he says: The heaven was made firm and solid as smoke. The heaven having therefore become solid in the midst of the waters made the upper half of them light, but the other half He left underneath. Why then and for what purpose were the waters placed above? Was it that we might drink them or that we might sail on them? For that there are waters above, David testifies, saying: And the water which is above the heavens.”
Source
“First of all, it is proved from the account of the creation that God divided the one place which extends from the earth to the first heaven, by placing in the middle the firmament, that is, the second heaven, thus making the one place into two places.”

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“יהי רקיע BE THERE AN EXPANSE — Let the expansion become fixed; for although the heavens were created on the first day, they were still in a fluid form, and they became solidified only on the second day at the dread command (literally, rebuke) of the Holy One, blessed be He, when he said “Let the firmament be stable” (Genesis Rabbah 4:2). It is to this that allusion is made in what is written in (Job 26:11): “The pillars of heaven were trembling” (i. e. they were unstable) — this was during the whole of the first day — and on the second (Job 26:11): “they were astonished at His rebuke”, like a man who stands immovable, amazed at the rebuke of one who terrifies him. בתוך המים IN THE MIDST OF THE WATERS — In the exact centre of the waters; because there is the same distance between the upper waters and the firmament as there is between the firmament and the waters that are upon the earth. Thus you may infer that they (the upper waters) are suspended in space by the command of the King (Genesis Rabbah 4:3).”
Source
1167
A.D.
Ibn Ezra Jewish
1089–1167
““And He said”, the Gaon said regarding the firmament (raki’a) things that could not be; rather its explanation is “extended”, like “they were extended” (vayerak’u) Exodus 39:3, “I shall extend them” (erka’em Samuel II 22:43, and similarly, “and He stretched them [i.e., the heavens] out like a tent for dwelling”. Isaiah 40:22. And how profound is the word of the one who says that the edges of the sun are with the edges of the waters of the oceans. Now this firmament is the atmosphere, for when the light coalesced over the earth and a dry wind from the earth, the blade/flame was changed and became the firmament. And thus did it say in a Psalm Psalms 104:2 “He stretches the heavens like a curtain… the one who makes roofbeams of water”. And it mentions the clouds and the wind and the earth element, which is higher than the water, and thus it writes, “for He founded it upon the seas” Psalms 24:2, “the One Who extends the earth over the waters" Psalms 136:6 and similarly, anyone who goes to the sea is called, “goes down”. The meaning of “the One Who calls to the waters of the sea” Amos 5:8 – so that they should ascend, referring to clouds, and afterwards, “and He pours them out”.”
Source
1270
A.D.
Ramban Jewish
1194–1270
“LET THERE BE A FIRMAMENT. G-d now said that the substance which had come into being first — that which He created from nought — should be a firmament, stretched as a tent in the midst of the waters, separating between waters and waters. It is possible that this is what the Rabbis intended by their saying, “Rav said, ‘The heavens were in a fluid form on the first day, and on the second day they solidified.’ Rav thus said, ‘Let there be a firmament means let the firmament become strong.’ Rabbi Yehudah the son of Rabbi Shimon said, ‘Let the firmament become like a plate, just as you say in the verse, And they did beat — [vayerak’u contains the same root as raki’a, firmament] — the gold into thin plates.’” IN THE MIDST OF THE WATERS. This means in the center of the waters, between the higher waters and the lower waters. For there is the same distance between the firmament and the waters upon the earth as between the higher waters and the firmament. Thus you may infer that the upper waters are suspended in space by the command of G-d. Thus it is explained in Bereshith Rabbah and in Rashi’s commentary. This is part of the process of creation [which those who know it are obliged to conceal]; so do not expect me to write anything about it, as the subject is one of the mysteries of the Torah, and the verses in their plain meaning do not require such an interpretation since Scripture itself did not go into it at length, and to give the interpretation is forbidden even to those who know it, and so much the more to us.”
Source

Reformation

c. 1500 – 1650
1550
A.D.
Sforno Jewish
c. 1475–1550
“"Let there be a firmament in the midst of the water" - let there be a [manifestation of] nature in the midst of elemental water similar to a sphere in their midst all around, separating by form part of them [i.e., the elemental waters] from the other part of them, in such a fashion that the upper part of the waters, near the [upper] atmosphere [lit.: air], would turn into vapor. Now behold, thereby, they [the waters] necessarily ascended to some boundary in the elemental air, and the air necessarily was subject to some transformation which made a place for a portion which was converted to vapor, and it expanded to a place much great in volume than its original place.”
Source

Post-Reformation

c. 1650 – 1900
1714
A.D.
Matthew Henry Reformed
1662–1714
“We have here an account of the second day's work, the creation of the firmament, in which observe, 1. The command of God concerning it: Let there be a firmament, an expansion, so the Hebrew word signifies, like a sheet spread, or a curtain drawn out. This includes all that is visible above the earth, between it and the third heavens: the air, its higher, middle, and lower, regions - the celestial globe, and all the spheres and orbs of light above: it reaches as high as the place where the stars are fixed, for that is called here the firmament of heaven (Gen 1:14, Gen 1:15), and as low as the place where the birds fly, for that also is called the firmament of heaven, Gen 1:20. When God had made the light, he appointed the air to be the receptacle and vehicle of its beams, and to be as a medium of communication between the invisible and the visible world; for, though between heaven and earth there is an inconceivable distance, yet there is not an impassable gulf, as there is between heaven and hell. This firmament is not a wall of partition, but a way of intercourse. See Job 26:7; Job 37:18; Psa 104:3; Amo 9:6. 2. The creation of it. Lest it should seem as if God had only commanded it to be done, and some one else had done it, he adds, And God made the firmament. What God requires of us he himself works in us, or it is not done. He that commands faith, holiness, and love, creates them by the power of his grace going along with his word, that he may have all the praise. Lord, give what thou commandest, and then command what thou pleasest. The firmament is said to be the work of God's fingers, Psa 8:3. Though the vastness of its extent declares it to be the work of his arm stretched out, yet the admirable fineness of its constitution shows that it is a curious piece of art, the work of his fingers. 3. The use and design of it - to divide the waters from the waters, that is, to distinguish between the waters that are wrapped up in the clouds and those that cover the sea, the waters in the air and those in the earth. See the difference between these two carefully observed, Deu 11:10, Deu 11:11, where Canaan is upon this account preferred to Egypt, that Egypt was moistened and made fruitful with the waters that are under the firmament, but Canaan with waters from above, out of the firmament, even the dew of heaven, which tarrieth not for the sons of men, Mic 5:7. God has, in the firmament of his power, chambers, store-chambers, whence he watereth the earth, Psa 104:13; Psa 65:9, Psa 65:10. He has also treasures, or magazines, of snow and hail, which he hath reserved against the day of battle and war, Job 38:22, Job 38:23. O what a great God is he who has thus provided for the comfort of all that serve him and the confusion of all that hate him! It is good having him our friend, and bad having him our enemy. 4. The naming of it: He called the firmament heaven. It is the visible heaven, the pavement of the holy city; above the firmament God is said to have his throne (Eze 1:26), for he has prepared it in the heavens; the heavens therefore are said to rule, Dan 4:26. Is not God in the height of heaven? Job 22:12. Yes, he is, and we should be led by the contemplation of the heavens that are in our eye to consider our Father who is in heaven. The height of the heavens should remind us of God's supremacy and the infinite distance there is between us and him; the brightness of the heavens and their purity should remind us of his glory, and majesty, and perfect holiness; the vastness of the heavens, their encompassing of the earth, and the influence they have upon it, should remind us of his immensity and universal providence.”
Source
1771
A.D.
John Gill Reformed
1697–1771
“And God said, let there be a firmament in the midst of the waters,.... On which the Spirit of God was sitting and moving, Gen 1:2 part of which were formed into clouds, and drawn up into heaven by the force of the body of fire and light already produced; and the other part left on the earth, not yet gathered into one place, as afterwards: between these God ordered a "firmament to be", or an "expanse" (v); something stretched out and spread like a curtain, tent, or canopy: and to this all those passages of Scripture refer, which speak of the stretching out of the heavens, as this firmament or expanse is afterwards called; seePsa 104:2 and by it is meant the air, as it is rendered by the Targum on Psa 19:1 we call it the "firmament" from the (w) word which the Greek interpreter uses, because it is firm, lasting, and durable: and it has the name of an expanse from its wide extent, it reaching from the earth to the third heaven; the lower and thicker parts of it form the atmosphere in which we breathe; the higher and thinner parts of it, the air in which fowls fly, and the ether or sky in which the sun, moon, and stars are placed; for all these are said to be in the firmament or expanse, Gen 1:17. These are the stories in the heavens the Scriptures speak of, Amo 9:6 and the air is divided by philosophers into higher, middle, and lower regions: and so the Targum of Jonathan places this firmament or expanse between the extremities of the heaven, and the waters of the ocean. The word in the Syriac language has the sense of binding and compressing (x); and so it is used in the Syriac version of Luk 6:38 and may denote the power of the air when formed in compressing the chaos, and dividing and separating the parts of it; and which it now has in compressing the earth, and the several parts that are in it, and by its compression preserves them and retains them in their proper places (y): and let it divide the waters from the waters; the waters under it from those above it, as it is explained in the next verse; of which more there. (v) "expansio", Montanus. Tigurine version; "extensio", Munster, Fagius, Vatablus, Aben Ezra; "expansum", Junius, Tremellius, Piscator, Drusius, Schmidt, Sept. "firmamentum", V. L. (w) Id. (x) Vid. Castell. Lex. col. 3647. Fuller. Miscell. Sacr. l. 1. c. 6. (y) Vid. Dickinson. Physica "vetus et vera", c. 7. sect. 13, 14. p. 88, 89.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“And God said, Let there be a firmament - Our translators, by following the firmamentum of the Vulgate, which is a translation of the στερεωμα of the Septuagint, have deprived this passage of all sense and meaning. The Hebrew word רקיע rakia, from רקע raka, to spread out as the curtains of a tent or pavilion, simply signifies an expanse or space, and consequently that circumambient space or expansion separating the clouds, which are in the higher regions of it, from the seas, etc., which are below it. This we call the atmosphere, the orb of atoms or inconceivably small particles; but the word appears to have been used by Moses in a more extensive sense, and to include the whole of the planetary vortex, or the space which is occupied by the whole solar system.”
Source
1849
A.D.
1774–1849
“A firmament. By this name is here understood the whole space between the earth and the highest stars. The lower part of which divideth the waters that are upon the earth, from those that are above in the clouds. (Challoner) — The Hebrew Rokia is translated stereoma, solidity by the Septuagint., and expansion by most of the moderns. The heavens are often represented as a tent spread out, Psalm. ciii. 3. (Calmet)”
Source
1871
A.D.
1871
“SECOND DAY. (Gen 1:6-8) firmament--an expanse--a beating out as a plate of metal: a name given to the atmosphere from its appearing to an observer to be the vault of heaven, supporting the weight of the watery clouds. By the creation of an atmosphere, the lighter parts of the waters which overspread the earth's surface were drawn up and suspended in the visible heavens, while the larger and heavier mass remained below. The air was thus "in the midst of the waters," that is, separated them; and this being the apparent use of it, is the only one mentioned, although the atmosphere serves other uses, as a medium of life and light.”
Source
1875
A.D.
Keil & Delitzsch Lutheran
1861–1875
“The Second Day. - When the light had been separated from the darkness, and day and night had been created, there followed upon a second fiat of the Creator, the division of the chaotic mass of waters through the formation of the firmament, which was placed as a wall of separation (מבדּיל) in the midst of the waters, and divided them into upper and lower waters. רקיע .s, from רקע to stretch, spread out, then beat or tread out, means expansum, the spreading out of the air, which surrounds the earth as an atmosphere. According to optical appearance, it is described as a carpet spread out above the earth (Psa 54:2), a curtain (Isa 40:22), a transparent work of sapphire (Exo 24:10), or a molten looking-glass (Job 37:18); but there is nothing in these poetical similes to warrant the idea that the heavens were regarded as a solid mass, a σιδήρεον, or χάλκεον or πολύχαλκον, such as Greek poets describe. The רקיע (rendered Veste by Luther, after the στερέωα of the lxx and firmamentum of the Vulgate) is called heaven in Gen 1:8, i.e., the vault of heaven, which stretches out above the earth. The waters under the firmament are the waters upon the globe itself; those above are not ethereal waters (Note: There is no proof of the existence of such "ethereal waters" to be found in such passages as Rev 4:6; Rev 15:2; Rev 22:1; for what the holy seer there beholds before the throne as "a sea of glass like unto crystal mingled with fire," and "a river of living water, clear as crystal," flowing from the throne of God into the streets of the heavenly Jerusalem, are wide as the poles from any fluid or material substance from which the stars were made upon the fourth day. Of such a fluid the Scriptures know quite as little, as of the nebular theory of La Place, which, notwithstanding the bright spots in Mars and the inferior density of Jupiter, Saturn, and other planets, is still enveloped in a mist which no astronomy will ever disperse. If the waters above the firmament were the elementary matter of which the stars were made, the waters beneath must be the elementary matter of which the earth was formed; for the waters were one and the same before the creation of the firmament.) But the earth was not formed from the waters beneath; on the contrary, these waters were merely spread upon the earth and then gathered together into one place, and this place is called Sea. The earth, which appeared as dry land after the accumulation of the waters in the sea, was created in the beginning along with the heavens; but until the separation of land and water on the third day, it was so completely enveloped in water, that nothing could be seen but "the deep," or "the waters" (Gen 1:2). If, therefore, in the course of the work of creation, the heaven with its stars, and the earth with its vegetation and living creatures, came forth from this deep, or, to speak more correctly, if they appeared as well-ordered, and in a certain sense as finished worlds; it would be a complete misunderstanding of the account of the creation to suppose it to teach, that the water formed the elementary matter, out of which the heaven and the earth were made with all their hosts. Had this been the meaning of the writer, he would have mentioned water as the first creation, and not the heaven and the earth. How irreconcilable the idea of the waters above the firmament being ethereal waters is with the biblical representation of the opening of the windows of heaven when it rains, is evident from the way in which Keerl, the latest supporter of this theory, sets aside this difficulty, viz., by the bold assertion, that the mass of water which came through the windows of heaven at the flood was different from the rain which falls from the clouds; in direct opposition to the text of the Scriptures, which speaks of it not merely as rain (Gen 7:12), but as the water of the clouds. Vid., Gen 9:12., where it is said that when God brings a cloud over the earth, He will set the rainbow in the cloud, as a sign that the water (of the clouds collected above the earth) shall not become a flood to destroy the earth again.) beyond the limits of the terrestrial atmosphere, but the waters which float in the atmosphere, and are separated by it from those upon the earth, the waters which accumulate in clouds, and then bursting these their bottles, pour down as rain upon the earth. For, according to the Old Testament representation, whenever it rains heavily, the doors or windows of heaven are opened (Gen 7:11-12; Psa 78:23, cf. Kg2 7:2, Kg2 7:19; Isa 24:18). It is in (or with) the upper waters that God layeth the beams of His chambers, from which He watereth the hills (Psa 104:13), and the clouds are His tabernacle (Job 36:29). If, therefore, according to this conception, looking from an earthly point of view, the mass of water which flows upon the earth in showers of rain is shut up in heaven (cf. Gen 8:2), it is evident that it must be regarded as above the vault which spans the earth, or, according to the words of Psa 148:4, "above the heavens." (Note: In Gen 1:8 the lxx interpolates καὶ εἶδεν ὁ Θεὸς ὅτι καλόν (and God saw that it was good), and transfers the words "and it was so" from the end of Gen 1:7 to the close of Gen 1:6 : two apparent improvements, but in reality two arbitrary changes. The transposition is copied from Gen 1:9, Gen 1:15, Gen 1:24; and in making the interpolation, the author of the gloss has not observed that the division of the waters was not complete till the separation of the dry land from the water had taken place, and therefore the proper place for the expression of approval is at the close of the work of the third day.)”
Source
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.