'Light' in the Bible

Now this is the gospel message we have heard from him and announce to you: God is light, and in him there is no darkness at all.

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.

On the other hand, I am writing a new commandment to you which is true in him and in you, because the darkness is passing away and the true light is already shining.

The one who says he is in the light but still hates his fellow Christian is still in the darkness.

The one who loves his fellow Christian resides in the light, and there is no cause for stumbling in him.