I have written about this before (here) but the propagation of therapeutic forgiveness among Christians continues to muddy the waters when it comes to to understanding biblical forgiveness.
Never in Scripture is there indication that "forgiving oneself" is expected, much less possible.
Forgiveness requires two people (or God and a person.) In a culture that continues to focus on self, the inevitable centering on self-esteem, self-worth, self-health and ultimately self-worship arises.
Now, if you were to Google "Bible Forgive Self" you would find a variety of sites, blogs, and postings about the subject. While the focus on "Bible" seeks to eliminate the unbiblical aspects of the search, the truth is that many Christians still propagate a self-forgiveness strategy as healthy and right.
To help clarify, I share some thoughts from others who hold to the veracity of Scripture:
Never does the Bible talk about the idea of “forgiving yourself.” We are told to forgive others when they trespass against us and seek forgiveness. When we ask for God’s forgiveness based upon Christ having already paid for our sins and our having trusted in Him as Savior and Lord, He forgives us. - gotQuestions.org
I have never preached that anybody should forgive themselves. At least, I don’t remember ever saying it. And I have never used it as a way of dealing with my own self-hatred or condemnation or whatever that it is supposed to deal with. I don’t think it is in the Bible, and the reason I don’t think it is in the Bible is that I think it would be intrinsically confusing about the nature of forgiveness if it were. Maybe the reason the Bible doesn’t think in these categories of self-forgiveness is that, to have forgiveness, you need a person who has been wronged and a person who did the wrong. - John Piper
While is a good thing to want to move beyond your mistakes and the consequences they have reaped, there are fundamental problems with even raising this question. As I stress throughout Unpacking Forgiveness, forgiveness is something that must occur between two parties. In light of that truth, it makes no more sense to talk about forgiving yourself than it does to talk about shaking your own hand. - Chris Brauns
Forgiveness isn’t something you can give yourself. It is something [God] has purchased for you. - Nancy Leigh DeMoss
Forgiveness requires both a victim and an offender, and so to forgive myself means that I am playing both roles. And so a part of me is allowed—even required—to play the victim for something that I did. But I shouldn’t get to play the victim, for I am the offender in this case. If I forgive myself, then I am asserting that I am a victim of my sin. - Justin Taylor
The person who says, “I just can’t forgive myself,” may simply be expressing an inability or unwillingness to grasp and receive God’s forgiveness. This seems to be the most common explanation behind “self-forgiveness” talk. We say that we can’t forgive ourselves because we really doubt that God has forgiven us. Or we don’t see our need for forgiveness from God, so we take over the job ourselves. Unsure of a solution to our real or perceived failure, we posit a need for self-forgiveness to satisfy our lingering guilt or to supplement God’s insufficient forgiveness. - Robert D. Jones
To seek forgiveness from yourself would be to ask yourself to forgive you for what you've done against yourself. But this doesn't make any sense. We are not the ones who make moral laws that we can break. Rather, God does that, so forgiving yourself just doesn’t make sense. - Matt Slick
And yet, there are many who would say "But that's just semantics, right?" No. It's not. It's more of a shift to understanding what is biblical and what is not and pushing against the cultural centering of self. BTW - this is nothing new. It's been going on since the Garden of Eden.
Forgiveness requires two people - the sinner and the sinned against.
Forgiveness is conditional.
"Forgive others as God has forgiven you" is what believers know to be true. It is vital to understand how he has forgiven you (or us.)