"We Must Forgive ALL The Apostle Paul, in his letter to the Romans, said that those who pass judgment on others are “inexcusable.” The moment we judge someone else, he explained, we condemn ourselves, for none is without sin. (Romans 2:1). Refusing to forgive is a grievous sin—one the Savior warned against. Jesus’s own disciples had “sought occasion against [each other] and forgave not one another in their hearts; and for this evil they were afflicted and sorely chastened” (D&C 64:8). Our Savior has spoken so clearly on this subject that there is little room for private interpretation. “I, the Lord, will forgive whom I will forgive,” but then He said, “… of you it is required to forgive all men” (D&C 64:10). May I add a footnote here? When the Lord requires that we forgive all men, that includes forgiving ourselves. Sometimes, of all the people in the world, the one who is the hardest to forgive—as well as perhaps the one who is most in need of our forgiveness—is the person looking back at us in the mirror. Doctrine and Covenants 64:8"

- Dieter F. Uchtdorf, "The Merciful Obtain Mercy,"