And God called the firmament, Heaven; and the evening and morning were the second day.

“AND G-D CALLED THE FIRMAMENT HEAVEN. On the second day He gave them this name when He clothed them with the form of the firmament for on the first day the heavens were still in the process of creation, but the name was not attached to them until they took on this form. The meaning of this name [shamayim — heavens] is as if it had the sign of a segol under the letter shin [the prefix shin thus voweled means “that” or “for”] just as in Shalamah (For why) should I be as one that veileth herself? there stands for asher - asher lamah (for why). Similarly in Ibn Ezra, ibid. Likewise here, the word shamayim is as if it said asher mayim (that waters), as is explained further in the text. It is thus as if He said that they [the heavens] are waters which have congealed and stretched like a tent in the midst of the upper and lower waters. By this name shamayim He has made known the secret of their creation. In the Gemara Tractate Chagigah, the Rabbis have said, “What is the meaning of the word shamayim? It means shem mayim.” If so, there is one mem missing here in the word shamayim on account of the adjoining of two similar letters, just as in the word yeruba’al [which stands for yareb bo ba’al — let Baal contend against him]. The word shamayim is thus as if it said shem mayim, meaning that “heaven” is the name given the waters when they took on a new form. This is the plain meaning of the verses in accordance with the way of Rashi’s writing, [may be regarded as made up of either of these words]: sa mayim (carries water), etc.” Rashi. and it conforms with the opinion of Rav which we have mentioned. Thus the names “heaven” and “earth” mentioned in the first verse point to the names by which they would be called in the future, as it would be impossible to make them known in any other manner. It is, however, more correct in accordance with the meaning of the verses that we say that the heavens mentioned in the first verse are the upper heavens, which are not part of the lower spheres but are above the merkavah (the Divine Chariot), just as it is stated, And over the heads of the living creatures there was the likeness of a firmament, like the color of the transparent ice, stretched forth over their heads above. It is on account of these higher heavens that the Holy One, blessed be He, is called He Who rideth upon the heavens. Scripture, however, did not relate anything concerning their creation, just as it did not mention the creation of the angels, the chayoth of the merkavah, and all Separate Intelligences which are incorporeal. Concerning the heavens, it mentioned only in a general way that they were created, meaning that they came forth from nought. On the second day He said that there should be a firmament in the midst of the waters, meaning that from the waters, the creation of which had already been mentioned, there should come forth an extended substance separating them [into two distinct waters]. These spherical bodies He also called “heavens” by the name of the first upper heavens. This is why they are called in this chapter “the firmament of the heaven” [rather than “heavens”] — And G-d set them in the firmament of the heaven — in order to explain that they are not the heavens mentioned by that name in the first verse but merely the firmaments called “heavens.” This likewise is the opinion of our Rabbis mentioned in Bereshith Rabbah, who state, “All Rabbis say it in the name of Rabbi Chananyah the son of Rabbi Pinchas, and Rabbi Yaakov the son of Rabbi Avin says it in the name of Rabbi Shmuel the son of Rabbi Nachman: Let there be a firmament in the midst of the waters — the middle drop of water congealed, and the lower heavens and the highest heaven of heavens were formed.” This saying of the Rabbis refers to the spherical bodies in which there are the lower heavens and the upper ones, called “the heavens of heavens,” as it is written: Praise ye Him, sun and moon; praise Him, all ye stars of light. Praise Him, ye heavens of heavens, and ye waters that are above the heavens. The heavens mentioned here in the first verse, in which is the Throne of the Holy One, Blessed be He, as it is written, The heaven is My throne, are the ones mentioned in the beginning of that Psalm: Praise ye the Eternal from the heavens; praise Him in the heights. Praise ye Him, all His angels. This interpretation is correct as far as the simple meaning of the verses is concerned. But there is yet a sublime and hidden secret in the name “the heaven” and in the name “the throne” for there is a heaven to the heavens, and a throne to the throne. Based on this, the Sages use the expressions, “In order that a man may first take upon himself the yoke of the kingdom of Heaven,” and “the fear of Heaven.”, 7a. Scripture likewise says, That the heavens do rule. The Sages also have a remarkable Midrash on the verse, And Thou hear in heaven. The worthy one will see all this alluded to in the first verse. Thus the verses have explained that the first created things were from nought, and the rest were derived from the first created substance. See no objection to this explanation from the saying of Rabbi Eliezer the Great, who states, “Whence were the heavens created? From the light of the garment of the Holy One, blessed be He.” [This would apparently indicate that the heavens were not created from nought but from another preceding substance.] This opinion is also found in Bereshith Rabbah. Since the Sages wanted to elevate the first substance to the utmost and make it ethereal, they did not find it feasible that the heavens, which are moving corporeal bodies possessing matter and form, were created from nought. Instead, they said “the light of the garment” was created first, and from it came forth the real substance of the heavens. And to the earth He gave another substance, not as minute as the first [substance from which the heavens were formed], and that is “the snow under the Throne of Glory,” for the Throne of Glory was first created, and from it came forth “the snow” under it, and from it [the “snow”] was formed the substance of the earth, which was third in the order of creation.”

“And God called the firmament heaven,.... Including the starry and airy heavens: it has its name from its height in the Arabic language, it being above the earth, and reaching to the third heaven; though others take the word "shamaim" to be a compound of two words, "sham" and "maim", that is, there are waters, namely, in the clouds of heaven: and the evening; and the morning were the second day; these together made up the space of twenty four hours, which was another natural day; the body of light, created on the first day, having again moved round the chaos in that space of time; or else the chaos had turned round on its own axis in that time, which revolution produced a second day; and which, according to Capellus, was the nineteenth of April, and according to Bishop Usher the twenty fourth of October. It is an observation that everyone may make, that the phrase, and God saw that it was good, is not used at the close of this day's work, as of the rest: the reason some Jewish writers give is, because the angels fell on this day; but it is a much better which Jarchi gives, and that is, because the work of the waters was not finished; it was begun on the second day, and perfected on the third (d); and therefore the phrase is twice used in the account of the third day's work: the Septuagint version adds it here indeed, but without any foundation. (d) Vid. Maimon. Moreh Nevochim, par. 2. c. 30.”