"Now it seems to me that we often make a mistake both about God's forgiveness of our sins and about the forgiveness we are told to offer to other people's sins. Take it first about God's forgiveness. I find that when It hink I am asking God to forgive me I am often in reality (unless I watch myself very carefully) asking Him to do something quite different. I am asking Him not to forgive me, but to excuse me. But there is all the difference in the world between forgiving and excusing. Forgiveness says, 'Yes, you have done this thing, but I accept your apology; I will never hold it against you and everything between us two will be exactly as it was before.' But excusing says, 'I see that you couldn't help it, or didn't mean it; you weren't really to blame.' If one was not really to blame then there is nothing to forgive. In that sense, forgiveness and excusing are almost opposites."
-Excerpt from On Forgiveness, a speech given by C.S. Lewis (written in collection of his speeches titled The Weight of Glory)