The interpretation timeline
Genesis 4:1 Douay-Rheims

And Adam knew Eve his wife: who conceived and brought forth Cain, saying: I have gotten a man through God.

A.D. 45 – 1875 10 witnesses 11 excerpts

Patristic

before A.D. 750
45
A.D.
c. 15 B.C.–A.D. 45
“XXXV. As all things then are confessed to be the possessions of God, and proved to be so by sound reasonings and testimonies, which cannot possibly be convicted of bearing false witness, for they are the sacred oracles which Moses has recorded in the Holy Scriptures that bear witness ; we must deprecate that mind which fancied that that which originated in a meeting with the outward sense was his own property, and which called it Cain, and said, " I have gotten a man by means of God,'" in this also greatly erring. But in what did he err? Because God was the cause, not the instrument; and what was born was created indeed through the agency of borne instrument, but was by all means called into existence by the great first cause ; for many things must co-operate in the origination of anything ; by whom, from what, by means of what, and why ? Now he by whom a thing originates is the cause ; that from which a thing is made is the material ; that by means of winch it was made is the instrument ; and why, is the object. For come now, suppose any one should say, what things must meet together, that any house or city may be made ? Must there not be a builder, and stones, and timber, and tools ? What then is the builder, but the cause by whom the house or city is built? And what are the stones and timber, but the materials of which the building is made ? And what are the tools, but the things by means of which it is made ? And for what reason is it built, except to serve as a shelter and protection? This is the object. Now passing on from these particular buildings, consider the greatest house or city, namely, this world, for you will find that God is the cause of it, by whom it was made. That the materials are the four elements, of which it is composed ; that the instrument is the word of God, by means of which it was made ; and the object of the building you will find to be the display of the goodness of the Creator. This is the discriminating opinion of men fond of truth, who desire to attain to true and sound knowledge ; but they who say that they have gotten anything by means of God, conceive that the cause is the instrument, the Creator namely, and the instrument the cause, namely, the human mind. And all sound reason would reproach Joseph for saying, " That the true interpretation of the dreams would be found out by means of God ;" for he should have said, that owing to him, as the cause indeed, would be the unfolding and accurate understanding of those things which were obscure ; for we are the instruments by whom the particular energies are developed, both in our states of tension and of relaxation ; but the Creator is " he who gives the blow which sets in motion" the faculties of body and soul, by whom all things are moved. Those then who are unable to distinguish between the differences of things must be instructed as ignorant; but those who, from a contentious spirit, invert the orders of the things signified, must be avoided as disputatious ; but those who, after an accurate investigation into the phasnomena which present themselves to them, assign its proper place to each of the objects discovered, must be praised as men who have attained to a true philosophy, and are void of error. For Moses says to those who fear lest they should be destroyed by the wicked man, who is pursuing them with all his host, " Stand still, and see the salvation which is from the Lord, and which he will work for you ;"f teaching them that salva- Genesis xL 8. + Exodus xiv. 13. tion is effected, not by means of God, but by him as the direct cause. A TREATISE o.v t;:e SACRIFICES OF ABEL ASD CAIN,”
Source
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“"Now, Adam had intercourse with his wife Eve." Consider when this happened. After their disobedience, after their loss of the garden, then it was that the practice of intercourse had its beginning. You see, before their disobedience they followed a life like that of the angels, and there was no mention of intercourse. How could there be, when they were not subject to the needs of the body? So, at the outset and from the beginning the practice of virginity was in force, but when through their indifference disobedience came on the scene and the ways of sin were opened, virginity took its leave for the reason that they had proved unworthy of such a degree of good things, and in its place the practice of intercourse took over for the future. Accordingly, consider, I ask you, dearly beloved, how great the esteem of virginity, how elevated and important a thing it is, surpassing human nature and requiring assistance from on high. I mean, for proof that those who practice virginity with enthusiasm demonstrate in the body the characteristics of incorporeal powers, listen to the words of Christ to the Sadducees: when they were discussing the question of resurrection and wanted to learn his view, they asked, "Master, there were seven brothers of our acquaintance. The eldest married and died without children, leaving his wife to his brother. The second died, and having no offspring left his wife to his brother; likewise with the third, fourth, fifth, sixth and seventh. So at the resurrection to which of the seven will the wife belong? After all, she belonged to them all." So what reply did Christ make to them? "You are mistaken, not understanding the Scriptures nor the power of God: at the resurrection, far from marrying or being given in marriage, they will be like angels." Do you see how those who have followed the vocation to virginity for the love of Christ imitate the life of angels through treading the earth and being clad in a body? I mean, the greater and more elevated the task, so much and even greater the laurels, the rewards and the good things promised to those who give evidence of the practice of good works along with this vocation. "Now, Adam had intercourse with his wife Eve," the text says, "and she conceived and gave birth to Cain." Since sin had come on the scene through the act of disobedience, and the sentence had the effect of making them liable to death, for the future God in his inventiveness arranged for the continuance of the human race according to his wisdom by allowing for the propagation of the race through intercourse. "She said, 'I have gained a human being, thanks to God.'" See how the imposition of the punishment brought the woman to her senses? She attributes the child she bore not to a natural process but to God, and displays her own gratitude. Do you see how the punishment proved an occasion of admonition to them? The text says, remember, "'I have gained a human being, thanks to God." ' It was not nature, she is saying, that presented me with the child; instead, grace from above has given him to me.”
Source
“After his disobedience, after their loss of the garden, then it was that the practice of intercourse had its beginning. You see, before their disobedience they followed a life like that of angels, and there was not mention of intercourse.”
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“Note that the name Cain means "ownership," which explains what was said at the time of his birth by his father or mother: "I have come into possession of a man through God."”

Scholastic

c. 1100 – 1500
1105
A.D.
Rashi Jewish
1040–1105
“(1) והאדם ידע AND THE MAN KNEW already before the events related above took place — before he sinned and was driven out of the Garden of Eden. So, also, the conception and birth of Cain took place before this. Had it been written, וידע אדם it would imply that after he was driven out children were born to him (Genesis Rabbah 22:2). קין — She called him so with reference to her use of the word. ה‘ — ;את קניתי is like ‘עם ה “with the Lord”; she meant to say: when He created me and my husband He created us by Himself, but in the case of this one we are copartners with Him (cf. Niddah 31a). את קיןאת אחיו את הבל —The threefold ‘את’ signify extension of the scope of the text, teaching that a twin sister was born with Cain, and that with Abel two were born; consequently the text states ותוסף “and she bore more’’ than the previous time (Genesis Rabbah 22:3).”
Source
1270
A.D.
Ramban Jewish
1194–1270
“AND SHE CONCEIVED AND BORE CAIN. The sense of it is that she gave birth to a son, and she called his name Cain [from the word kanah, acquisition], because she said, I have gotten a man with [the help of] the Eternal. In a similar sense is the verse, And she conceived and bore Enoch, and many similar verses in this chapter and in other places. “Eth Hashem (with the Eternal). When He created me and my husband He created us by Himself, but in the case of this one, we are co-partners with him.” Thus the words of Rashi. The correct interpretation appears to me to be that she said: “This son will be for me an acquisition for the Eternal, for when we shall die he will exist in our stead to worship his Creator.” This is also the opinion of Onkelos who translated eth hashem to mean “before the Eternal.” [The word eth in the following verses is translated] in a similar sense: And it shall be shown ‘eth hakohen’ (the priest), meaning to the priest; And David came near ‘eth ha’am’ (the people), meaning to the people. Or it may be that eth hashem has the same interpretation as in the verses: And Enoch walked ‘eth ha’elokim’ (with G-d); Noah walked ‘eth ha’elokim’ (with G-d)., 6:9. The sense here in the verse before us would thus be: I have acquired a man to walk with G-d. Now she [Eve] called one son by a name indicating “acquisition,” and the second one she called Abel, denoting “vanity” because man’s acquisition is likened to vanity. But she did not wish to say so explicitly. Therefore, no reason is written for the name of the second son. The secret received by tradition concerning Abel is very profound.”
Source

Post-Reformation

c. 1650 – 1900
1714
A.D.
Matthew Henry Reformed
1662–1714
“Adam and Eve had many sons and daughters, Gen 5:4. But Cain and Abel seem to have been the two eldest. Some think they were twins, and, as Esau and Jacob, the elder hated and the younger loved. Though God had cast our first parents out of paradise, he did not write them childless; but, to show that he had other blessings in store for them, he preserved to them the benefit of that first blessing of increase. Though they were sinners, nay, though they felt the humiliation and sorrow of penitents, they did not write themselves comfortless, having the promise of a Saviour to support themselves with. We have here, I. The names of their two sons. 1. Cain signifies possession; for Eve, when she bore him, said with joy, and thankfulness, and great expectation, I have gotten a man from the Lord. Observe, Children are God's gifts, and he must be acknowledged in the building up of our families. It doubles and sanctifies our comfort in them when we see them coming to us from the hand of God, who will not forsake the works and gifts of his own hand. Though Eve bore him with the sorrows that were the consequence of sin, yet she did not lose the sense of the mercy in her pains. Comforts, though alloyed, are more than we deserve; and therefore our complaints must not drown our thanksgivings. Many suppose that Eve had a conceit that this son was the promised seed, and that therefore she thus triumphed in him, as her words may be read, I have gotten a man, the Lord, God-man. If so, she was wretchedly mistaken, as Samuel, when he said, Surely the Lord's anointed is before me, Sa1 16:6. When children are born, who can foresee what they will prove? He that was thought to be a man, the Lord, or at least a man from the Lord, and for his service as priest of the family, became an enemy to the Lord. The less we expect from creatures, the more tolerable will disappointments be. 2. Abel signifies vanity. When she thought she had obtained the promised seed in Cain, she was so taken up with that possession that another son was as vanity to her. To those who have an interest in Christ, and make him their all, other things are as nothing at all. It intimates likewise that the longer we live in this world the more we may see of the vanity of it. What, at first, we are fond of, as a possession, afterwards we see cause to be dead to, as a trifle. The name given to this son is put upon the whole race, Psa 39:5. Every man is at his best estate Abel - vanity. Let us labour to see both ourselves and others so. Childhood and youth are vanity. II. The employments of Cain and Abel. Observe, 1. They both had a calling. Though they were heirs apparent to the world, their birth noble and their possessions large, yet they were not brought up in idleness. God gave their father a calling, even in innocency, and he gave them one. Note, It is the will of God that we should every one of us have something to do in this world. Parents ought to bring up their children to business. "Give them a Bible and a calling (said good Mr. Dod), and God be with them." 2. Their employments were different, that they might trade and exchange with one another, as there was occasion. The members of the body politic have need one of another, and mutual love is helped by mutual commerce. 3. Their employments belonged to the husbandman's calling, their father's profession - a needful calling, for the king himself is served of the field, but a laborious calling, which required constant care and attendance. It is now looked upon as a mean calling; the poor of the land serve for vine-dressers and husbandmen, Jer 52:16. But the calling was far from being a dishonour to them; rather, they were an honour to it. 4. It should seem, by the order of the story, that Abel, though the younger brother, yet entered first into his calling, and probably his example drew in Cain. 5. Abel chose that employment which most befriended contemplation and devotion, for to these a pastoral life has been looked upon as being peculiarly favourable. Moses and David kept sheep, and in their solitudes conversed with God. Note, That calling or condition of life is best for us, and to be chosen by us, which is best for our souls, that which least exposes us to sin and gives us most opportunity of serving and enjoying God.”
Source
1771
A.D.
John Gill Reformed
1697–1771
“And Adam knew Eve his wife,.... An euphemism, or modest expression of the act of coition. Jarchi interprets it, "had known", even before he sinned, and was drove out of the garden; and so other Jewish writers, who think he otherwise would not have observed the command, "be fruitful and multiply": but if Adam had begotten children in a state of innocence, they would have been free from sin, and not tainted with the corruption of nature after contracted; but others more probably think it was some considerable time after; according to Mer Thudiusi, or Theodosius (t), it was thirty years after he was driven out of paradise: and she conceived and bare Cain; in the ordinary way and manner, as women ever since have usually done, going the same time with her burden. Whether this name was given to her first born by her, or by her husband, or both, is not said: it seems to have been given by her, from the reason of it after assigned. His name, in Philo Byblius (u), is Genos, which no doubt was Cain, in Sanchoniatho, whom he translated; and his wife, or the twin born with him, is said to be Genea, that is, "Cainah": the Arabs call her Climiah (v) and the Jewish writers Kalmenah (w); who are generally of opinion, that with Cain and Abel were born twin sisters, which became their wives. And said, that is, Eve said upon the birth of her firstborn: I have gotten a man from the Lord; as a gift and blessing from him, as children are; or by him, by his favour and good will; and through his blessing upon her, causing her to conceive and bear and bring forth a son: some render it, "I have gotten a man, the Lord" (x); that promised seed that should break the serpents head; by which it would appear, that she took that seed to be a divine person, the true God, even Jehovah, that should become man; though she must have been ignorant of the mystery of his incarnation, or of his taking flesh of a virgin, since she conceived and bare Cain through her husband's knowledge of her: however, having imbibed this notion, it is no wonder she should call him Cain, a possession or inheritance; since had this been the case, she had got a goodly one indeed: but in this she was sadly mistaken, he proved not only to be a mere man, but to be a very bad man: the Targum of Jonathan favours this sense, rendering the words,"I have gotten a man, the angel of the Lord.'' (t) Apud Abulpharag. Hist. Dynast. p. 6. (u) Apud Euseb. Praepar. Evangel. l. 1. c. 10. p. 34. (v) Abulpharag. ib. (w) Shalshaleth Hakabala, fol. 74. 2. (x) "virum Dominum", Fagius, Helvicus, Forster, Schindler, Luther, Pellican, Cocceius; "virum qui Jehovah est", Schmidt.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“I have gotten a man from the Lord - Cain, קין, signifies acquisition; hence Eve says קנתי kanithi, I have gotten or acquired a man, את יהוה eth Yehovah, the Lord. It is extremely difficult to ascertain the sense in which Eve used these words, which have been as variously translated as understood. Most expositors think that Eve imagined Cain to be the promised seed that should bruise the head of the serpent. This exposition really seems too refined for that period. It is very likely that she meant no more than to acknowledge that it was through God's peculiar blessing that she was enabled to conceive and bring forth a son, and that she had now a well-grounded hope that the race of man should be continued on the earth. Unless she had been under Divine inspiration she could not have called her son (even supposing him to be the promised seed) Jehovah; and that she was not under such an influence her mistake sufficiently proves, for Cain, so far from being the Messiah, was of the wicked one; Jo1 3:12. We may therefore suppose that את היוה eth Yehovah, The Lord, is an elliptical form of expression for מאת יהוה meeth Yehovah, From The Lord, or through the Divine blessing.”
Source
1849
A.D.
1774–1849
“Through God . Hebrew may signify also “even God,” as if she thought this was the promised seed, who, as Onkelos paraphrases it, would serve the Lord. (Calmet) — So little could she foresee the future conduct of Cain, whose name may be derived either from kone, possession and acquisition, or from kun, lamentation. The latter interpretation would have been better verified by the event, and the name of Abel, vanity, or sorrow, for which his parents allege no reason, might also have been reversed, on account of his justice, for which he is canonized by Christ himself, and declared the Just. Pious and significant names were imposed by either parent. Cain was the second man. He was not conceived till after the fall, and was therefore the first born in original sin. (Haydock)”
Source
1875
A.D.
Keil & Delitzsch Lutheran
1861–1875
“The propagation of the human race did not commence till after the expulsion from paradise. Generation in man is an act of personal free-will, not a blind impulse of nature, and rests upon a moral self-determination. It flows from the divine institution of marriage, and is therefore knowing (ידע) the wife. - At the birth of the first son Eve exclaimed with joy, "I have gotten (קניתי) a man with Jehovah;" wherefore the child received the name Cain (קין from קוּן = קנה, κτᾶσθαι). So far as the grammar is concerned, the expression את־יהוה might be rendered, as in apposition to אישׁ, "a man, the Lord" (Luther), but the sense would not allow it. For even if we could suppose the faith of Eve in the promised conqueror of the serpent to have been sufficiently alive for this, the promise of God had not given her the slightest reason to expect that the promised seed would be of divine nature, and might be Jehovah, so as to lead her to believe that she had given birth to Jehovah now. את is a preposition in the sense of helpful association, as in Gen 21:20; Gen 39:2, Gen 39:21, etc. That she sees in the birth of this son the commencement of the fulfilment of the promise, and thankfully acknowledges the divine help in this display of mercy, is evident from the name Jehovah, the God of salvation. The use of this name is significant. Although it cannot be supposed that Eve herself knew and uttered this name, since it was not till a later period that it was made known to man, and it really belongs to the Hebrew, which was not formed till after the division of tongues, yet it expresses the feeling of Eve on receiving this proof of the gracious help of God. Gen 4:2-7 But her joy was soon overcome by the discovery of the vanity of this earthly life. This is expressed in the name Abel, which was given to the second son (הבל, in pause הבל, i.e., nothingness, vanity), whether it indicated generally a feeling of sorrow on account of his weakness, or was a prophetic presentiment of his untimely death. The occupation of the sons is noticed on account of what follows. "Abel was a keeper of sheep, but Cain was a tiller of the ground." Adam had, no doubt, already commenced both occupations, and the sons selected each a different department. God Himself had pointed out both to Adam-the tilling of the ground by the employment assigned him in Eden, which had to be changed into agriculture after his expulsion; and the keeping of cattle in the clothing that He gave him (Gen 3:21). Moreover, agriculture can never be entirely separated from the rearing of cattle; for a man not only requires food, but clothing, which is procured directly from the hides and wool of tame animals. In addition to this, sheep do not thrive without human protection and care, and therefore were probably associated with man from the very first. The different occupations of the brothers, therefore, are not to be regarded as a proof of the difference in their dispositions. This comes out first in the sacrifice, which they offered after a time to God, each one from the produce of his vocation. - "In process of time" (lit., at the end of days, i.e., after a considerable lapse of time: for this use of ימים cf. Gen 40:4; Num 9:2) Cain brought of the fruit of the ground a gift (מנחה) to the Lord; and Abel, he also brought of the firstlings of his flock, and indeed (vav in an explanatory sense, vid., Ges. 155, 1) of their fat," i.e., the fattest of the firstlings, and not merely the first good one that came to hand. חלבים are not the fat portions of the animals, as in the Levitical law of sacrifice. This is evident from the fact, that the sacrifice was not connected with a sacrificial meal, and animal food was not eaten at this time. That the usage of the Mosaic law cannot determine the meaning of this passage, is evident from the word minchah, which is applied in Leviticus to bloodless sacrifices only, whereas it is used here in connection with Abel's sacrifice. "And Jehovah looked upon Abel and his gift; and upon Cain and his gift He did not look." The look of Jehovah was in any case a visible sign of satisfaction. It is a common and ancient opinion that fire consumed Abel's sacrifice, and thus showed that it was graciously accepted. Theodotion explains the words by καὶ ἐνεπύρισεν ὁ Θεός. But whilst this explanation has the analogy of Lev 9:24 and Jdg 6:21 in its favour, it does not suit the words, "upon Abel and his gift." The reason for the different reception of the two offerings was the state of mind towards God with which they were brought, and which manifested itself in the selection of the gifts. Not, indeed, in the fact that Abel brought a bleeding sacrifice and Cain a bloodless one; for this difference arose from the difference in their callings, and each necessarily took his gift from the produce of his own occupation. It was rather in the fact that Abel offered the fattest firstlings of his flock, the best that he could bring; whilst Cain only brought a portion of the fruit of the ground, but not the first-fruits. By this choice Abel brought πλείονα θυσίαν παρὰ Κάΐν, and manifested that disposition which is designated faith (πίστις) in Heb 11:4. The nature of this disposition, however, can only be determined from the meaning of the offering itself. The sacrifices offered by Adam's sons, and that not in consequence of a divine command, but from the free impulse of their nature as determined by God, were the first sacrifices of the human race. The origin of sacrifice, therefore, is neither to be traced to a positive command, nor to be regarded as a human invention. To form an accurate conception of the idea which lies at the foundation of all sacrificial worship, we must bear in mind that the first sacrifices were offered after the fall, and therefore presupposed the spiritual separation of man from God, and were designed to satisfy the need of the heart for fellowship with God. This need existed in the case of Cain, as well as in that of Abel; otherwise he would have offered no sacrifice at all, since there was no command to render it compulsory. Yet it was not the wish for forgiveness of sin which led Adam's sons to offer sacrifice; for there is no mention of expiation, and the notion that Abel, by slaughtering the animal, confessed that he deserved death on account of sin, is transferred to this passage from the expiatory sacrifices of the Mosaic law. The offerings were expressive of gratitude to God, to whom they owed all that they had; and were associated also with the desire to secure the divine favour and blessing, so that they are to be regarded not merely as thank-offerings, but as supplicatory sacrifices, and as propitiatory also, in the wider sense of the word. In this the two offerings are alike. The reason why they were not equally acceptable to God is not to be sought, as Hoffmann thinks, in the fact that Cain merely offered thanks "for the preservation of this present life," whereas Abel offered thanks "for the forgiveness of sins," or "for the sin-forgiving clothing received by man from the hand of God." To take the nourishment of the body literally and the clothing symbolically in this manner, is an arbitrary procedure, by which the Scriptures might be made to mean anything we chose. The reason is to be found rather in the fact, that Abel's thanks came from the depth of his heart, whilst Cain merely offered his to keep on good terms with God-a difference that was manifested in the choice of the gifts, which each one brought from the produce of his occupation. This choice shows clearly "that it was the pious feeling, through which the worshiper put his heart as it were into the gift, which made the offering acceptable to God" (Oehler); that the essence of the sacrifice was not the presentation of a gift to God, but that the offering was intended to shadow forth the dedication of the heart to God. At the same time, the desire of the worshipper, by the dedication of the best of his possessions to secure afresh the favour of God, contained the germ of that substitutionary meaning of sacrifice, which was afterwards expanded in connection with the deepening and heightening of the feeling of sin into a desire for forgiveness, and led to the development of the idea of expiatory sacrifice. - On account of the preference shown to Abel, "it burned Cain sore (the subject, 'wrath,' is wanting, as it frequently is in the case of חרה, cf. Gen 18:30, Gen 18:32; Gen 31:36, etc.), and his countenance fell" (an indication of his discontent and anger: cf. Jer 3:12; Job 29:24). God warned him of giving way to this, and directed his attention to the cause and consequences of his wrath. "Why art thou wroth, and why is thy countenance fallen?" The answer to this is given in the further question, "Is there not, if thou art good, a lifting up" (sc., of the countenance)? It is evident from the context, and the antithesis of falling and lifting up (נפל and נשׂא), that פּנים must be supplied after שׂאת. By this God gave him to understand that his look was indicative of evil thoughts and intentions; for the lifting up of the countenance, i.e., a free, open look, is the mark of a good conscience (Job 11:15). "But if thou art not good, sin lieth before the door, and its desire is to thee (directed towards thee); but thou shouldst rule over it." The fem. חטּאת is construed as a masculine, because, with evident allusion to the serpent, sin is personified as a wild beast, lurking at the door of the human heart, and eagerly desiring to devour his soul (Pe1 5:8). היטיב, to make good, signifies here not good action, the performance of good in work and deed, but making the disposition good, i.e., directing the heart to what is good. Cain is to rule over the sin which is greedily desiring him, by giving up his wrath, not indeed that sin may cease to lurk for him, but that the lurking evil foe may obtain no entrance into his heart. There is no need to regard the sentence as interrogative, "Wilt thou, indeed, be able to rule over it?" (Ewald), nor to deny the allusion in בּו to the lurking sin, as Delitzsch does. The words do not command the suppression of an inward temptation, but resistance to the power of evil as pressing from without, by hearkening to the word which God addressed to Cain in person, and addresses to us through the Scriptures. There is nothing said here about God appearing visibly; but this does not warrant us in interpreting either this or the following conversation as a simple process that took place in the heart and conscience of Cain. It is evident from Gen 4:14 and Gen 4:16 that God did not withdraw His personal presence and visible intercourse from men, as soon as He had expelled them from the garden of Eden. "God talks to Cain as to a wilful child, and draws out of him what is sleeping in his heart, and lurking like a wild beast before his door. And what He did to Cain He does to every one who will but observe his own heart, and listen to the voice of God" (Herder). But Cain paid no need to the divine warning. Gen 4:8 He "said to his brother Abel." What he said is not stated. We may either supply "it," viz., what God had just said to him, which would be grammatically admissible, since אמר is sometimes followed by a simple accusative (Gen 22:3; Gen 44:16), and this accusative has to be supplied from the context (as in Exo 19:25); or we may supply from what follows some such expressions as "let us go into the field," as the lxx, Sam., Jonathan, and others have done. This is also allowable, so that we need not imagine a gap in the text, but may explain the construction as in Gen 3:22-23, by supposing that the writer hastened on to describe the carrying out of what was said, without stopping to set down the words themselves. This supposition is preferable to the former, since it is psychologically most improbable that Cain should have related a warning to his brother which produced so little impression upon his own mind. In the field "Cain rose up against Abel his brother, and slew him." Thus the sin of Adam had grown into fratricide in his son. The writer intentionally repeats again and again the words "his brother," to bring clearly out the horror of the sin. Cain was the first man who let sin reign in him; he was "of the wicked one" (Jo1 3:12). In him the seed of the woman had already become the seed of the serpent; and in his deed the real nature of the wicked one, as "a murderer from the beginning," had come openly to light: so that already there had sprung up that contrast of two distinct seeds within the human race, which runs through the entire history of humanity.”
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.