Now this is the message we have heard from Him and declare to you: God is light, and there is absolutely no darkness in Him.
References for 1 John 1:5
If we say, "We have fellowship with Him," and walk in darkness, we are lying and are not practicing the truth.
References for 1 John 1:6
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.