This is how we know that we know him: if we keep his commandments.

 In this passage and in 1 John 2:10-11, the light is identified with love and the dark with hate. That is to say, the end of this process is a world where love reigns supreme and hate is banished for ever. Christ has come in the individual heart when a man's whole being is ruled by love; and he will have come in the world of men when all men obey his commandment of love. The coming and reign of Jesus is identical with the coming and reign of love. 