The Apostle Paul writes In Philippians 3:12-14 that he forgets what is behind in order to press on toward the goal God has called him to.
One reason Paul could put his past behind him was that he knew he was forgiven and that God had put his past behind him. I can imagine that he must have struggled with the fact that he had persecuted and killed Christians in his past, but on that Damascus road he found Jesus and from that point on he was a forgiven man, and he had accepted that forgiveness.
Maybe that is what is keeping you enslaved to your past—you really don’t feel like God has forgiven you. Well, if you sincerely asked him to in the name of Jesus and through his shed blood, then he had to forgive you or he would be a liar—and God is not a liar. So, maybe you just don’t feel forgiven. That’s where you must ignore those feelings and live by faith.
When the enemy comes to haunt you with those past sins, quote 1 John 1:9 over and over—out loud if possible: “If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.” Throw the word of God right back in satan’s face. God purifies from all unrighteousness, so don’t let him tell you the lie that your sin is too much or too awful.
In order to put your past behind you, you must learn to think correctly. The place where your past gets to you is in your mind—those thoughts and nightmares and memories which swirl around in your head and cripple you mentally and emotionally. The battlefield is your mind.
The Apostle Paul could put his past behind him because he was learning to bring every thought into captivity and allow the mind of Christ in him to control his thinking. In that same letter to the Philippians, chapter 4 verse 8, he tells us what we should think about: Things that are true, noble, right, pure, lovely, admirable, excellent and praiseworthy. The past that haunts you does not fall into those categories, does it? So, that means you must learn to practice this principle and bring every thought into captivity so that you don’t think about the dreadful past. How do you do that?
By replacing wrong thoughts with right thoughts. I’ve written a book entitled Think About What You Think About, and this could help you learn how to get rid of the thoughts of your past which drive you crazy.