"If anyone says he loves God but hates his brother, he is a liar."

John's doctrine is founded in the teaching of Jesus, which is founded on the Old Testament, since God says clearly: "You must love your neighbour as yourself. I am Yahweh" (Leviticus 19:18). Jesus raises this to a higher level: "You must love each other as I have loved you". Thus, all human relationships and social intercourse is under the protection and guidance of God's Law. Love, of course, is motivated and guided by that freedom which is an intrinsic part of human existence. Nevertheless, though it seems a paradox, love can be commanded. Still, even when commanded, love is not merely a matter of obeying a law or a commandment but is ultimately a disposition of life. Love ultimately demands a moral direction of life which transcends the directions which the law gives.

John uses "brother" where the Old Testament uses "neighbour". A close examination shows that "neighbour" is simply anyone who deserves love and the same is true of "brother" or "sister" in the Christian sense. Sin lies in the dichotomy of one's professed love for God and one's daily human behaviour.