Ephesians 6:16 - "Above all, taking the shield of faith with which you will be able to quench all the fiery darts of the enemy"
We are called to make our prayers in faith, and to stand against the enemy in faith. I know what it is like to have bad thoughts come back into your mind, and my initial reaction was fear. I didn't want to become the man I was in the past, and my own thoughts scared me. However, I realized that God was greater than my enemy. I put my trust in God to take away my sinful thoughts. It took a lot of prayer, and some fasting, but I eventually was able to break free of my bad thoughts. What defeated my enemy was faith in God. Even though my first prayers for help did not seem like they were working, I repeated them with great frequency (Luke 18:1-8). God will remain faithful to you, if you faithfully look to him for all of your help. May he be with you and save you from all wickedness.