I have only one thing to add to what Joseph Prince says here. It is what Jesus taught us to pray:
And forgive our sins — for we have forgiven those who sinned against us.. . . . .Luke 11:4
We have been forgiven much, he took our punishment on the cross and lead by example. Dying on the cross, in more pain than anyone can imagine, some of his last words were:-
“Father, forgive these people,” Jesus said, “for they don’t know what they are doing.”. . . . .Luke 23:34
As a Christian, God does not give us an option when it comes to forgiving people who have wronged or hurt us. The commandments regarding this subject are clearer than most any other commandments in the Bible. We do not get to bear grudges, in fact we should try not to remain angry for longer than a day. This may seem impossible to you but, nothing is impossible with God.
We have to trust God that He is a God of justice and that vengence is His. But to have the power to love and forgive, we must first ourselves be right with God. Some of us have been through things so heinous and horrible that we think we could never forgive those who so abused us. In our own strength we could Not. When it is deeply wounding and hurtful we need to ask Jesus to take that hurt and give us the strength and power to forgive, that we ourselves do not have. We don't do this because the abusers deserve forgiveness - THEY DON'T!!! But then neither did we and yet God forgave us. He commands we forgive and that's why we do it!