A popular saying about holding onto anger, resentment or unforgiveness is that it's like taking poison and waiting for the other person to die. I believe that the converse of that statement is, if anything, even more true. Forgiveness is like taking medicine and waiting for the other person to heal. On the surface, both statements seem to be equally futile. I can't get the person I'm angry with to die by drinking poison myself, and it seems just as likely that I would not be able to bring any kind of healing to a person whom I'm trying to forgive by taking medicine myself. But the amazing thing about the Atonement is that healing can come both to us when we are the ones who are doing the forgiving and to those whom we are seeking to forgive. Sometimes we may need to take a lot of medicine to start to feel the effects of our Savior's healing power, and we might have to take that medicine for a long, long time before the other person also starts to heal, but I do know that there is an undeniable power in forgiveness. Wouldn't it be better for us to drink the medicine of forgiveness and bring healing both to ourselves and to those who have wronged us, than it would be to drink the bitter poison of anger and resentment and slowly die inside while we affect the one who hurt us not at all? Like many medicines, forgiveness can be a bitter cup to swallow, but when we do, we are following in the path of our Savior, who drained the medicine of forgiveness down to the dregs in the hopes that He could bring healing to all of God's children.
