1 John 3:1-10 New King James Version (NKJV)
The Command to Love
3 Behold what manner of love the Father has bestowed on us, that we should be called children of [a]God! Therefore the world does not know [b]us, because it did not know Him. 2 Beloved, now we are children of God; and it has not yet been revealed what we shall be, but we know that when He is revealed, we shall be like Him, for we shall see Him as He is. 3 And everyone who has this hope in Him purifies himself, just as He is pure.
Sin and the Child of God
4 Whoever commits sin also commits lawlessness, and sin is lawlessness. 5 And you know that He was manifested to take away our sins, and in Him there is no sin. 6 Whoever abides in Him does not sin. Whoever sins has neither seen Him nor known Him.
7 Little children, let no one deceive you. He who practices righteousness is righteous, just as He is righteous. 8 He who sins is of the devil, for the devil has sinned from the beginning. For this purpose the Son of God was manifested, that He might destroy the works of the devil. 9 Whoever has been born of God does not sin, for His seed remains in him; and he cannot sin, because he has been born of God.
The Imperative of Love
10 In this the children of God and the children of the devil are manifest: Whoever does not practice righteousness is not of God, nor is he who does not love his brother.