What if there is something in my past that, looking back, I feel so ashamed of that now it’s hard for me to believe, or keep believing, that God has truly forgiven me?
That is an issue that even sincere believers in Christ face sometimes. It might be that even if you believe God has forgiven you in Christ and confessed that sin to Him, and stood on the promise of 1 John 1:9, still, you have a lingering guilt feeling any time you recall it.
To deal with this feeling of guilt it is important to know what the source is.
A twinge of guilt from a long past action that you confessed already could be false guilt, and you might just need to keep reminding yourself that you are forgiven and that God will not bring it up again (More on that later). However, there could be other reasons.
Assuming you have read the teaching from Unit 2 on confession of sin, have you applied it?
It’s also important to be honest with God about what our sin truly was. Don’t confess to a lesser crime, so to speak, when you know what the real problem is. For example, it might be easy on my ego to say, “God, I’m sorry I got angry at so-and-so” when the much bigger problem was my own selfishness in the first place--which created the conflict. If that's the case, ask God to show you what the issue is (Psalm 139:23-24). Yet if the Holy Spirit does not soon bring to mind something specific, do not become overly introspective.
Another reason we might still feel guilty is if we hurt someone but never reconciled and asked their forgiveness, or if we stole something but never repaid it. Making restitution is essential to a good conscience, even if it has been many years. If that’s the case, do it now. Pick up the phone, write a note (or a check!) and make it right.
What if that person is no longer alive? We wish would could make restitution or ask forgiveness! But it’s too late. First of all know that God understands and has forgiven you because of Christ. Don’t let the devil, the accuser, tell you otherwise. But the regret can be overwhelming. It is a lingering consequence of a past action.
John Newton, the slave trader turned believer felt this keenly. Out of that regret he wrote the hymn, “Amazing Grace.” Newton could not go back and ask forgiveness for the hundreds he had traded or the scores who had died in the miserable conditions on his ship crossing the ocean. At one point he had even talked a young sailor out of following Christ and that man died years later screaming in fear of hell. But he could make a difference with his life. Not only did he write the hymn, he humbly served God and was a key influence in ending the British slave trade. His regret was turned to positive action. Read more at this link.
Paul, too, faced regret over his past life as a persecutor of the church. Though totally forgiven in Christ, he could not undo it all. It was one of the factors that propelled him to preach the grace of Christ to all, and to do all he could to build the church. Even after decades of building the church, Paul described his life to his friend Timothy this way,
“...Christ Jesus came into the world to save sinners, among whom I am foremost of all. Yet for this reason I found mercy, so that in me as the foremost, Jesus Christ might demonstrate His perfect patience as an example for those who would believe in Him for eternal life.” (1 Timothy 1:15-16).
Paul didn’t wallow in false guilt. He was convinced of his total forgiveness and eternal salvation in Christ. He wasn’t trying to earn God’s favor. He had it in full because of Christ. Nor was he trying to “compensate” in some strange psychological twist. In fact, just the opposite. He was all the more amazed at God’s grace because it could save even him.
John Newton put it this way centuries later:
Amazing grace, how sweet the sound
That saved a wretch like me.
I once was lost, but now am found,
Was blind, but now I see.
Every experience is an education. Even our own mistakes And we can help others to not fall into the same mistakes.