Verses 13-24. - Hate and death contrasted with love and life (verses 13-15); generous love, which has its pattern in the self-sacrifice of Christ (verses 16, 17); sincere love, which is the ground of our boldness toward God, who has commanded us to love (verses 18-24). Verse 13. - Human nature is the same as of old. There is still a Cain, the world, hating its Abel, the Church. Therefore marvel not, brethren, if the world hateth you. Here only does St. John use the address, "brethren," which is appropriate to the subject of brotherly love. Elsewhere his readers are "children" or "beloved." The "if" (εἰ with indicative) expresses no doubt as to the fact, but states it gently and conditionally.

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.Marvel not, my brethren, if the world hate you. By "the world" is meant the inhabitants of the world, the wicked part of them; these hate the saints, though without a cause, any just cause, and for no other reason, but because they are chosen and called out of the world, and do not live the wicked life they do: and this hatred of theirs is not at all to be wondered at; so it was from the beginning, and has been in all ages since; immediately upon the fall there was enmity between the seed of the woman and the seed of the serpent, which showed itself in Cain, the instance just given, who hated and murdered his righteous brother; Ishmael, that was born after the flesh, persecuted Isaac, that was born after the Spirit; and as it was then, it is now, the Jews persecuted the prophets of old, and hated Christ and his apostles. This is the common lot of all the saints, of all that will live godly in Christ Jesus; and therefore it should not be reckoned a strange and unusual thing; it always was so, even from the beginning, as soon as ever there were two sorts of persons, good and bad, righteous and wicked. This is a corollary or conclusion drawn from the above instance of Cain.