Cornelius Plantinga:
It’s hard to repent. And while it’s hard enough to repent before a perfect God, it’s even harder to repent before an imperfect human being. To admit that you have injured or neglected another person, then to go the person and say, “I’m sorry. I’m ashamed. Will you forgive me?”—to do this is mortifying. It kills us to do it. You need to be a big person to give it a serious try. That’s the paradox of repentance, says, C.S. Lewis. Only a bad person needs to repent. Only a good person can do it. (Beyond Doubt: Faith-Building Devotions on Questions Christians Ask, 242).