| Barnes' Notes on the Bible Not as Cain - Not manifesting the spirit which Cain did. His was a most remarkable and striking instance of a want of love to a brother, and the case was well adapted to illustrate the propriety of the duty which the apostle is enjoining. See Genesis 4:4-8. Who was of that wicked one - Of the devil; that is, he was under his influence, and acted from his instigation. And wherefore slew he him? - Because his own works were evil, and his brother's righteous." He acted under the influence of envy. He was dissatisfied that his own offering was not accepted, and that his brother's was. The apostle seems desirous to guard those to whom he wrote against the indulgence of any feelings that were the opposite of love; from anything like envy toward more highly favored brethren, by showing to what this would lead if fairly acted out, as in the case of Cain. A large part of the crimes of the earth have been caused, as in the murder of Abel, by the want of brotherly love. Nothing but love would be necessary to put an end to the crimes, and consequently to a large part of the misery, of the world.
Clarke's Commentary on the BibleNot as Cain - Men should not act to each other as Cain did to his brother Abel. He murdered him because he was better than himself. But who was Cain? Εκ του πονηρου ην, he was of the devil. And who are they who, through pride, lust of power, ambition, gain, etc., murder each other in wars and political contentions? Εκ του πονηρου εισι. To attempt to justify the principle, and excuse the instigators, authors, abettors, etc., of such wars, is as vain as it is wicked. They are opposed to the nature of God, and to that message which he has sent to man from the beginning: Love one another. Love your enemies. Surely this does not mean, Blow out their brains, or, Cut their throats. O, how much of the spirit, temper, and letter of the Gospel have the nations of the world, and particularly the nations of Europe, to learn! And wherefore slew he him? - What could induce a brother to imbrue his hands in a brother's blood? Why, his brother was righteous, and he was wicked; and the seed of the wicked one which was in him induced him to destroy his brother, because the seed of God - the Divine nature, was found in him.
Gill's Exposition of the Entire BibleNot as Cain,.... That is, let us not be like him, or do as he did, hate the brethren. The apostle illustrates brotherly love by its contrary, in the instance of Cain, who was the first instance and example of hatred of the brethren, and of fratricide, and a very detestable one, by which he would dissuade from so vile and abominable a practice: who was of that wicked one; Satan, a child of his, an imitator of him, one that appeared to be under his influence, and to belong unto him. So the Jews say of Cain (n), that "he was of the side of the serpent (the old serpent the devil); and as the way of the serpent is to slay and to kill, so Cain immediately became a murderer.'' And again, "because Cain came from the side of the angel of death, he slew his brother (o);'' though they say that he afterwards repented, and became worthy of paradise (p). And slew his brother; see Genesis 4:8. According to the tradition of the Jews (q) he struck a stone into his forehead, and killed him: and wherefore slew he him? what was the cause and occasion of it? what moved him to it? because his own works were evil, and his brother's righteous; or "his work", as the Ethiopic version reads: the sacrifice which he offered up, which, though it was not evil as to the matter and substance of it, yet was so, being offered with an evil mind, and with an hypocritical heart, and without faith in the sacrifice of Christ, and so was unacceptable to God; whereas, on the other hand, the sacrifice his brother brought was offered up in the faith of Christ, by which he obtained a testimony that he was righteous, and that the work he did was a righteous work, being done in faith, and so was acceptable to God; which Cain perceiving, was filled with envy, and this put him upon killing him. The Jews (r) relate the occasion of it after this manner; "Cain said to Abel his brother, come, and let us go out into the open field; and when they were both out in the open field, Cain answered and said to Abel his brother, there is no judgment, nor Judge, nor another world; neither will a good reward be given to the righteous, nor vengeance be taken on the wicked; neither was the world created in mercy, nor is it governed in mercy; or why is thy offering kindly accepted, and mine is not kindly accepted? Abel answered and said to Cain, there is judgment, and there is a Judge, and there is another world; and there are gifts of a good reward to the righteous, and vengeance will be taken on the wicked; and the world was created in mercy, and in mercy it is governed, for according to the fruit of good works it is governed; because that my works are better than thine, my offering is kindly accepted, and thine is not kindly accepted; and they both strove together in the field, and Cain rose up against Abel his brother, and slew him.'' In the Hebrew text in Genesis 4:8; there is an extraordinary large pause, as if a discourse of this kind, which passeth between the two brothers, was to be inserted. Philo the Jew says (s), that in the contention or dispute between Cain and Abel, Abel attributed all things to God, and Cain ascribed everything to himself; so that the controversy was about grace and works, as now; and as then Cain hated his brother upon this account, so now carnal men hate and persecute the saints, because they will not allow their works to be the cause of justification and salvation: and from hence also it may be observed, that a work may be, as to the matter of it, good, and yet as to its circumstances, and the end and view of it, evil. (n) Midrash Ruth in Zohar in Gen. fol. 42. 4. (o) Zohar in ib. fol. 43. 1.((p) Ib. fol. 41. 1, 2.((q) Targum Jon. in Gen. iv. 8. Pirke Eliezer, c. 21. (r) Targum Hieros. & Jon. in Gen. iv. 8. (s) Quod Det. Potior. p. 161.
Vincent's Word StudiesCain who was (Κάΐ́ν ἧν) Who is not in the Greek. The construction is irregular. Lit., as Rev., not as Cain was of the evil one. Slew (ἔσφαξεν) The verb occurs only in John, and only here outside of Revelation. Originally, to slay by cutting the throat; so in Homer, of cattle: "the suitor train who slay (σφάζουσι) His flocks and slow-paced beeves with crooked horns." "Odyssey," i., 92. To slaughter victims for sacrifice: "Backward they turned the necks of the fat beeves, And cut their throats (ἕσφαζαν), and flayed the carcasses." "Iliad," i., 459. Thence, generally, to slay or kill. Wherefore (χάριν τίνος) Lit., on account of what. Χάριν for the sake of, on account of, is elsewhere placed after the genitive. See Ephesians 3:1, Ephesians 3:14; 1 Timothy 5:14; Galatians 3:19.
Geneva Study Bible{12} Not as Cain, who was of that wicked one, and slew his brother. {13} And wherefore slew he him? Because his own works were evil, and his brother's righteous. (12) An amplification taken from the contrary example of Cain who slew his brother. (13) A short digression: Let us not marvel that we are hated by the world for doing our duty, for such was the condition of Abel who was a just person: and who would not rather be like him than Cain?
People's New Testament 3:12 Not as Cain, who was of that wicked one. Cain, who hated and slew his brother (Ge 4:8), is an extreme type of children of the devil. This hater and murderer is condemned far more severely in the Scriptures than the disobedient Adam.
Wesley's Notes 3:12 Who was of the wicked one - Who showed he was a child of the devil by killing his brother. And wherefore slew he him - For any fault? No, but just the reverse; for his goodness.
Jamieson-Fausset-Brown Bible Commentary12. who-not in the Greek. of that wicked one-Translate, "evil one," to accord with "Because his own works were evil." Compare 1Jo 3:8, "of the devil," in contrast to "of God," 1Jo 3:10. slew he him? Because his own works were evil, and his brother's righteous-through envy and hatred of his brother's piety, owing to which God accepted Abel's, but rejected Cain's offering. Enmity from the first existed between the seed of the woman and the seed of the serpent.
Matthew Henry's Concise Commentary3:11-15 We should love the Lord Jesus, value his love, and therefore love all our brethren in Christ. This love is the special fruit of our faith, and a certain sign of our being born again. But none who rightly know the heart of man, can wonder at the contempt and enmity of ungodly people against the children of God. We know that we are passed from death to life: we may know it by the evidences of our faith in Christ, of which love to our brethren is one. It is not zeal for a party in the common religion, or affection for those who are of the same name and sentiments with ourselves. The life of grace in the heart of a regenerate person, is the beginning and first principle of a life of glory, whereof they must be destitute who hate their brother in their hearts.
Matthew Henry's Whole Bible CommentaryVerses 11-13 The apostle, having intimated that one mark of the devil's children is hatred of the brethren, takes occasion thence, I. To recommend fraternal Christian love, and that from the excellence, or antiquity, or primariness of the injunction relating thereto: And this is the message (the errand or charge) which you heard from the beginning (this came among the principal parts of practical Christianity), that we should love one another, v. 11. We should love the Lord Jesus, and value his love, and consequently love all the objects of it, and thereupon all our brethren in Christ. II. To dissuade from what is contrary thereto, all ill-will towards the brethren, and that by the example of Cain. His envy and malignity should deter us from harbouring the like passion, and that upon these accounts:-1. It showed that he was as the first-born of the serpent's seed; even he, the eldest son of the first man, was of the wicked one. He imitated and resembled the first wicked one, the devil. 2. His ill-will had no restraint; it proceeded so far as to contrive and accomplish murder, and that of a near relation, and that in the beginning of the world, when there were but few to replenish it. He slew his brother, v. 12. Sin, indulged, knows no bound. And, 3. It proceeded so far, and had in it so much of the devil, that he murdered his brother for religion's sake. He was vexed with the superiority of Abel's service, and envied him the favour and acceptance he had with God. And for these he martyred his brother. And wherefore slew he him? Because his own works were evil, and his brother's righteous, v. 12. Ill-will will teach us to hate and revenge what we should admire and imitate. And then, III. To infer that it is no wonder that good men are so served now: Marvel not, my brethren, if the world hate you, v. 13. The serpentine nature still continues in the world. The great serpent himself reigns as the God of this world. Wonder not then that the serpentine world hates and hisses at you who belong to that seed of the woman that is to bruise the serpent's head. | 
