Some comments on repentance and forgiveness:
Repentance is a kind and merciful law. It is far-reaching and all-inclusive. It has many elements and includes a sorrow for sin, a confession of sin, an abandonment of sin, a restitution of sin, and then the living of the commandments of the Lord, and this includes the forgiveness of others, even the forgiving of those who sin against us.
President Spencer W. Kimball. Faith Precedes the Miracle. Salt Lake City: Deseret Book Company, 1993, p. 189.
Why does the Lord ask you to love your enemies and to return good for evil? That you might have the benefit of it. It does not injure the one who hate so much when you hate a person, especially if he is far removed and does not come in contact with you, but the hate and the bitterness canker your unforgiving heart.
Ibid., p. 191