If we claim to be without sin, we deceive ourselves and the truth is not in us.  If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.  If we claim we have not sinned, we make him out to be a liar and his word is not in us.

My dear children, I write this to you so that you will not sin. But if anybody does sin, we have an advocate with the Father—Jesus Christ, the Righteous One.  He is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world.

1 John 1:8-2:2