Scripture Who/When/Where What's it About?
3 Nephi 13:14 Jesus teaching the Nephites If you forgive, you will be forgiven
Mosiah 26:29-31 The voice of the Lord to Alma Forgive others
D&C 1:32 1831 Repent and be forgiven
D&C 64:10 1831 The Lord forgives who he wants, we must forgive all.
D&C 58:42 1831 If we repent, the Lord will remember it no more

Scripture Stories
Nephi forgiving his brothers (again) - Nephi 7:16-21
Jesus on the cross - Luke 23:34
Joseph forgiving his brothers - Gen. 45:1-5
Nephites during King Benjamin's talk - Mosiah 4:1-3

Hymns to read -
Nay Speak no Ill - #233

Quotes on Forgiveness HERE