Forgiving does not mean excusing. Many people seem to think it does. They think that if you ask them to forgive someone who has cheated or bullied them, you are trying to make out that there was really no cheating or no bullying. [In other words, that you say, “Well, it never really happened.”] But if that were so, there would be nothing to forgive. They keep on replying, “But I tell you the man broke a most solemn promise.” Exactly. That is precisely what you have to forgive. (This doesn’t mean you must necessarily believe his next promise; it does mean that you must make every effort to kill every trace of resentment in your own heart, every wish to humiliate or hurt him or to pay him [back]).
The difference between this situation and the one in which you are asking God’s forgiveness is this: in our own case, we accept excuses too easily; in other people’s, we do not accept them easily enough. As regards my own sins, it is a safe bet (though not a certainty) that the excuses are not really so good as I think. As regard other men’s sins against me, it is a safe bet (though not a certainty) that the excuses are better than I think. One must therefore begin by attending carefully to everything which may show that the other man was not so much to blame as we thought. But even if he is absolutely fully to blame, we still have to forgive him. And even if ninety-nine percent of his apparent guilt can be explained away by really good excuses, the problem of forgiveness begins with the one percent of guilt that is left over.… To be a Christian means to forgive the inexcusable, because God has forgiven the inexcusable in you.
This is hard. It is perhaps not so hard to forgive a single great injury, but to forgive the incessant provocations of daily life—to keep on forgiving the bossy mother-in-law, the bullying husband, the nagging wife, the selfish daughter, the deceitful son, and so on—how can we do it?
How can we do it? Only, I think, by remembering where we stand, by meaning our words when we say in our prayers each night, “Forgive our trespasses as we forgive those that trespass against us.” We are offered forgiveness on no other terms. To refuse it is to refuse God’s mercy for ourselves. There is no hint of exceptions, and God means what he says.
C.S. Lewis, "On Forgiveness," in Fern-seed and Elephants, Ed. Walter Hooper (Glasgow: Collins, 1975), 42-43