We are enabled and commanded by God to forgive all manner of trespass committed against us just as He has forgiven us.
In 1987 I suffered a sudden major heart attack. The pain was enormous and at first I passed into unconsciousness. When I came to, I was extremely weak and could barely feel my pulse. I was slumped over and felt that I would fall any second. I believed I had about 4 seconds to live. I called out to God, "Where are you Lord, I am coming home. Why don't I see You?" I expected to see Him, but instead He comforted me with His words of love. He said to me; "You don't see Me, because you are not going to die now. Listen well, my son. The worst thing you could do right now is to die and leave resentment in the earth. Whatever you do, do not leave resentment in the earth."
I knew immediately the situation He was referring to. A few hours later while in the intensive care unit I dealt with it. Praise the Lord!
Forgive, do not retain. Forgiveness is of grace. Give it freely, just as you have been given it. It does not have to be earned, accepted or wanted by the other party. Whenever possible make it known to them, however release all unforgiveness...dissolve it...forget it.
Whatever you do, do not die and leave resentment in the earth.