But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus Christ, his Son, cleanses us from all sin.

 (ii) It tells us that God is self-revealing. Above all things light is seen; and it illumines the darkness round about it. To say that God is light is to say that there is nothing secretive or furtive about him. He wishes to be seen and to be known by men. 