Psalm 103:12 "As far as the east is from the west, so far hath he removed our transgressions from us."
I don't know about you but I have a problem at times with remembering my sin from my life before I got saved. And I did a lot of things. The devil likes to bring them back up and throw them in my face. But you know what God says? I John 2:12 "I write unto you, little children, because your sins are forgiven you for his name's sake." God has forgiven my sins. Those were taken care of on Calvary. At the time I confessed my sins to Him and asked Him to come into my heart and save me He forgave and forgot them. He removed them from me as far as the east is from the west. My husband describes it this way...when you go north...you will eventually go south. When you go south....you will eventually go north. But when you go east you always go east and when you go west you always go west. You will NEVER catch up to your sin!! You'll never find yourself going opposite as long as you keep going forward. So we must forget those past sins. So if you know you've been forgiven...forget about them. God has!!
Now...here is something else I was thinking about in relation to this subject. We have a tendency to allow ourselves to go back to a sin that was committed against us and being upset all over again with the person or people who committed that sin against us. God tells us we are to forgive those who trespass against us. And what comes with forgiveness? Forgetting!! God has forgiven us our trespasses and forgotten them and if we are to be like Christ then we must do the same. I think this is a very difficult thing for some people to do. But with prayer and God's grace I believe we can do this.
When you find yourself going back to past sins...just remember that God says "What sins are you talking about?" He has forgotten and so should we. Both the sins we ourselves have committed and the sins others have committed against us.