5 This is the message we have heard from him and proclaim to you, that God is light, and in him is no darkness at all. 6 If we say we have fellowship with him while we walk in darkness, we lie and do not practice the truth. 7 But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin. 8 If we say we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. 10 If we say we have not sinned, we make him a liar, and his word is not in us.
2:1 My little children, I am writing these things to you so that you may not sin. But if anyone does sin, we have an advocate with the Father, Jesus Christ the righteous. 2 He is the propitiation for our sins, and not for ours only but also for the sins of the whole world. (ESV)