Everyone has regrets. You regret sinful choices and stupid choices. Choices as small as hitting the snooze, and choices as large as the person you married, the career you chose, and the house you purchased. How are you to handle and think about those past decisions?
You are to forget the past and remember the past.
Paul tells us in Phil 3:13 that we are to “forget what lies behind and reach forward to what lies ahead.” The word “forgetting,” in the context, means not to the let the past hinder your present. During a race, a runner does not look behind him (i.e., at the past) because looking behind him will hinder his present. So when Paul tells you to forget the things behind, he is saying to forget the past sins and mistakes that hinder and trip you up in the present.
Peter, on the other hand, tells us in 2 Peter 1 that sometimes you “forget your purification from your former sins” (v. 9). In essence, Peter tells you that you have forgotten that you are a sinner. You have forgotten what you have been saved from. You have forgotten the gospel. You have become short sighted. So, in this sense, “forgetting,” according to Peter, means that you should never forget that you are saved and being saved by grace. To put it positively, remember that you are still a sinner saved every day by God’s grace. Never forget where you came from, so you don’t become proud, arrogant, and boastful.
Putting these two passages together, Peter and Paul do not contradict each other. Paul tells us to forget the past in the sense of the not letting the past hinder our present. And Peter tells us to remember the past in the sense of not forgetting where we have come from.
This, then, is the answer to the question: how do you deal with your past sins and mistakes you regret? If you have repented of your sins, you should not dwell on them so that your past does not hinder your present—press forward; move on. But, at the same time, let the past always be a reminder of where you have come from so that you never forget God’s grace to you in the gospel. Think of it like driving. When driving, you keep your eyes forward. Occasionally, you look in the rear-view mirror to gain perspective on how far you have come. But don’t keep your eyes on the rear-view mirror, or you will crash.
Forget and remember.