From Day 53 of Rolf Gates and Katrina Kenison's book Meditations from the Mat:
Forgiveness can never be entirely self-serving. We do forgive others for our own spiritual growth, but the most important reason for forgiveness is our belief in interconnectedness. Because we are all one, what we cannot forgive in others we cannot forgive in ourselves; what we withhold from others we withhold from ourselves. The judgments we pronounce upon others are ultimately being pronounced upon ourselves, because there is no you and no me, there is only we. Forgiveness, therefore, is an act of self-love, and by loving ourselves we love the whole of humanity. Ensnared in our own condemnation, we can find no peace. Forgiveness frees us from this predicament and lays the foundations upon which our spiritual life can be built.