At the end of the Lord’s Prayer, the Savior reminds the Nephites that if they are to pray sincerely “forgive us our debts, as we forgive our debtors” (3 Nephi 13:11), they must be willing to forgive others: “For, if ye forgive men their trespasses your heavenly Father will also forgive you; But if ye forgive not men their trespasses neither will your Father forgive your trespasses.” (3 Nephi 3:14-15.)
President Spencer W. Kimball has explained what it means to forgive others:
Remember that we must forgive even if our offender did not repent and ask forgiveness… .It frequently happens that offenses are committed when the offender is not aware of it. Something he has said or done is misconstrued or misunderstood. The offended one treasures in his heart the offense, adding to it such other things as might give fuel to the fire and justify his conclusions. Perhaps this is one of the reasons why the Lord requires that the offended one should make the overtures toward peace… .
To the Nephites the Lord said:
“… if … thy brother hath aught against thee—Go thy way unto thy brother, and first be reconciled to thy brother, and then come unto me with full purpose of heart, and I will receive you.” (3 Nephi 12:23-24.)
And to the disciples in Judea he said:
"Therefore if thou bring thy gift to the altar, and there rememberest that thy brother hath ought against thee;
“Leave there thy gift before the altar and go thy way; first be reconciled to thy brother, and then come and offer thy gift.” (Matt. 6:23-24.)
Do we follow that commandment or do we sulk in our bitterness, waiting for our offender to learn of it and to kneel to us in remorse?
And this reconciliation suggests also forgetting. Unless you forget, have you forgiven? …
The Lord forgets when he has forgiven, and certainly must we. He inspired Isaiah to say:
“I, even I, am he that blotted out thy transgressions for mine own sake, and will not remember thy sins.” (Isaiah 43:25.)
And again in our dispensation, he said:
“Behold, he who has repented of his sins, the same is forgiven; and I, the Lord, remember them no more.” (D&C 58:42.)
And we are instructed by him that:
“… thou shalt forgive him with all thine heart …” (D&C 98:45.)
No bitterness of past frictions can be held in memory if we forgive with all our hearts. (Conference Report, October 1949, pp. 132-33.)