The inability, or reluctance, to forgive is our greatest failing. It is the cause of the majority of personal strife as well as global war. When you hold on to your anger, resentment, or disappointment in other people, you sabotage your own happiness. You use your precious spiritual energy on those negative emotions, when you could be using that power to live a joyous life, attract abundance, and improve the conditions of the world around you. An inability or unwillingness to forgive constricts you, draws you inward, whereas forgiveness gives you the opportunity to expand and open the channels of abundance in your life.
— Kathleen McGowan, The Source of Miracles, p. 125-126