Verse 15. - As in 1 John 4:20, St. John passes at once from not loving to hating, treating the two as equivalent. He takes no account of the neutral ground of indifference. He that is not for his brother is against him. Indifference is hate quiescent, there being nothing to excite it. Love is the only security against hate. And as every one who does not love is potentially a hater, so every hater is potentially a murderer. A murderer is a hater who expresses his hatred in the most emphatic way. A hater who does not murder abstains for various reasons from this extreme way of expressing his hate. But the temper of the two men is the same; and it is obvious (οἴδατε "ye know what needs no evidence") that every murderer is incapable of possessing eternal life. It is the murderous temper, not the act of homicide, that excludes from eternal life. St. John, of course, does not mean that murder is an unpardonable sin; but he shows that hate and death go together, as love and life, and that the two pairs are mutually exclusive. How can life and the desire to extinguish life be compatible? It is very forced to interpret ἀνθρωποκτόνος as either "destroyer of his own soul," or "destroyer of the hated man's soul," by provoking him to return hate for hate.

3:11-15 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.Whosoever hateth his brother is a murderer,.... A soul murderer, as the Ethiopic version renders it; not only of himself, for every sinner, by sinning, wrongs and destroys his own soul; but of his brother whom he hates: he is a murderer of him in his heart, even as he that lusts after a woman hath committed adultery with her in his heart, out of which arise murders, as well as adulteries; it is not only taking away life, but also causeless anger, malice, and hatred, that is a breach of the sixth command; see Matthew 5:21;

and ye know that no murderer hath eternal life abiding in him; he has not the grace of life, or the beginning of eternal life in him; he has no meetness for it, being unregenerate; and no right unto it, being unrighteous; nor has he the earnest and pledge of it, being destitute of the Spirit of God; all which a regenerate man has, and has them abiding in him: not but that the sin of murder may be forgiven; a man guilty of it may truly repent, and have pardoning grace applied unto him, and enjoy eternal life, through the grace of the Spirit, and the blood and righteousness of Christ; but without these he is so far from having eternal life, that he is not only punishable with a corporeal death, according to the laws of God and man; but he is exposed unto, and will die the second, or an eternal death.