Here is a reflection by C.S. Lewis on forgiveness that accompanies Psalm 51, which I preached on yesterday, in the C.S. Lewis Bible.
Real forgiveness means looking steadily at the sin, the sin that is left over without any excuse, after all allowances have been made, and seeing it in all is horror, dirt, meanness, and malice, and nevertheless being wholly reconciled to the man who has done it. That, and only that, is forgiveness, and that we can always have from God if we ask for it.[†]
C.S. Lewis, “My Sin Is Ever Before Me,” from The C.S. Lewis Bible NRSV (New York: HarperCollins, 2010), 606.