Finding Forgiveness Personal and Spiritual Perspectives by Jim McManus and Stephanie Thornton.

Often when people are hurt, or their trust and confidence have been shattered, the only way they know to get on with life is to lock themselves into unforgiveness. Other people might feel that forgiveness in some way involves condoning or minimizing a wrong, or letting the guilty party off the hook. The most surprising people sometimes display a truly puzzling inability to forgive.