1 John 1:7

1:7 But if we walk in the light as he himself is in the light, we have fellowship with one another and the blood of Jesus his Son cleanses us from all sin.

1 John 2:9-10

2:9 The one who says he is in the light but still hates his fellow Christian is still in the darkness. 2:10 The one who loves his fellow Christian resides in the light, and there is no cause for stumbling in him.