It is the blood of Jesus Christ that cleanses us from all sin; and if we confess our sins, he is faithful and just to forgive us our sins, and cleanse us from all unrighteousness.  Please see the Bible verses below:

1 John 1:5-10, "This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all.  If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth: But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin.  If we say that we have no sin, we deceive ourselves, and the truth is not in us.  If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.  If we say that we have not sinned, we make him a liar, and his word is not in us."