1 John 1:8 If we say that 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 that we have not sinned, we make him a liar, and his word is not in us.
Here verses 8 and 10 tell us that if we say we have no sin that the truth is not in us and that we are liars and deceiving ourselves. Also it says that we make God a liar and there fore His word is not in us.The word tells us that all have sinned and fall short come short of the glory of God. Verse 9 tells us how we can get cleansed from our sin. If we will confess sins to God he is faithful and just to forgive us and cleanse us from all unrighteousness. He does ask that we learn from past mistakes and not make them in the future. When He forgives our sins there gone as far as the east is from the west never to be seen by God again . they are now covered by the blood of Jesus Christ and that is all God can see. We need to in a mode of repentance all the time because of how Satan attacks us.