1See how great a love the Father has given to us, that we should be called children of God! For this cause the world doesn’t know us, because it didn’t know him. 2Beloved, now we are children of God. It is not yet revealed what we will be; but we know that when he is revealed, we will be like him, for we will see him just as he is. 3Everyone who has this hope set on him purifies himself, even as he is pure.
4Everyone who sins also commits lawlessness. Sin is lawlessness. 5You know that he was revealed to take away our sins, and no sin is in him. 6Whoever remains in him doesn’t sin. Whoever sins hasn’t seen him and doesn’t know him.
7Little children, let no one lead you astray. He who does righteousness is righteous, even as he is righteous. 8He who sins is of the devil, for the devil has been sinning from the beginning. To this end the Son of God was revealed: that he might destroy the works of the devil. 9Whoever is born of God doesn’t commit sin, because his seed remains in him, and he can’t sin, because he is born of God. 10In this the children of God are revealed, and the children of the devil. Whoever doesn’t do righteousness is not of God, neither is he who doesn’t love his brother. 11For this is the message which you heard from the beginning, that we should love one another— 12unlike Cain, who was of the evil one and killed his brother. Why did he kill him? Because his deeds were evil, and his brother’s righteous.
13Don’t be surprised, my brothers, if the world hates you. 14We know that we have passed out of death into life, because we love the brothers. He who doesn’t love his brother remains in death. 15Whoever hates his brother is a murderer, and you know that no murderer has eternal life remaining in him.
16By this we know love, because he laid down his life for us. And we ought to lay down our lives for the brothers. 17But whoever has the world’s goods and sees his brother in need, then closes his heart of compassion against him, how does God’s love remain in him?
18My little children, let’s not love in word only, or with the tongue only, but in deed and truth. 19And by this we know that we are of the truth and persuade our hearts before him, 20because if our heart condemns us, God is greater than our heart, and knows all things. 21Beloved, if our hearts don’t condemn us, we have boldness toward God; 22so whatever we ask, we receive from him, because we keep his commandments and do the things that are pleasing in his sight. 23This is his commandment, that we should believe in the name of his Son, Jesus Christ, and love one another, even as he commanded. 24He who keeps his commandments remains in him, and he in him. By this we know that he remains in us, by the Spirit which he gave us.
John states a principle, evidenced by his use of “whoever.” This alludes back to Cain and Abel. John now applies it to the Christian life. John is still talking about Christians’ attitudes toward other Christians. His use of “brother” indicates this. He will further define “hate” in a later verse.
Once again, what they “know” (οἴδατε) is by instruction. This is something they have been taught. He states a second principle: “No murderer has eternal life remaining (abiding) in him.” This is often interpreted to mean that murderers are unregenerate. However, Christians do commit murder and remain saved. Peter (1 Peter 4:15) commands Christians not to suffer as murderers, and James (James 4:1-2) accuses his readers of murdering. Both are addressing Christians and affirm the possibility in a Christian’s life. Paul, too, identifies murder as one of the “works of the flesh” that a Christian can do when not filled with the Spirit (Gal 5:19-21).
If “remaining” (abiding) is understood in the way Jesus used it in the Upper Room, John’s point is that murderers are not being influenced by eternal life. Taking this one step further, John indicates in his prologue that eternal life is a person he had handled and seen, Jesus. Thus, it seems better to see John saying that when a Christian hates another Christian, Jesus, eternal life incarnate, is not influencing that person. Hatred and murder do not originate with Jesus. When the life of Jesus, eternal life, is expressed in the actions of a believer, it produces love, not hatred.