The answer is: it's not about him.
Forgiveness in your heart is about your healing and your release from the pain and trap of unforgiveness. People who have not forgiven others for what they have done live in hurt and pain, they cannot do some things without the sensitive scar of their past hurt lashing out in pain. If a person has been hurt by a father, then every time they hear of the mention of a father or a loving father they feel anger and hurt because of what happened before.
Because Jesus died for our offences against God, our sins were forgiven. Whatever we had done to God in our lives they no longer count against us. God's forgiveness of us had a cost in Jesus' life.
Because Jesus has paid the price and we are forgiven people, he empowers us to forgive others. Because Jesus forgave us, his power can enable us to forgive others, if we are willing. Ability comes through Jesus' work on the cross; willingness comes by our choice.
When we are hurt, we can come to God and say, "God, this person has harmed me and done these awful things, and it makes me angry and bitter and hurt. But I choose not to hold onto these things; I choose to let them go. I'm willing to forgive them God, give me the strength to forgive them. I choose not to hold anything against them but to let it go, and even bless them."
Forgiveness is not about what the other person has done, or how bad the thing was. Forgiveness does not depend on whether that guy deserves it, does not depend on whether he is repentant, does not depend on whether he will do it again or not. It does not mean you have to confront your offender and say sorry to him. It is not about his actions but about whether you're willing to let go of the poison that he has inflicted on you. He has done something to you, and as long as you hold onto that offence it will eat at your soul, poison you and eventually change you into something awful. God doesn't want to see you become twisted by anger, bitterness, unforgiveness and pain; forgiving someone in your heart is not God's punishment to the afflicted but a way out of their affliction and the only way to find release from it.
To try and make amends with that person is called reconciliation and is different from forgiveness. It cannot always happen because it involves both parties agreeing to restore peace. Reconciliation is not always possible but always preferable; God tells us that "in so far as it is possible" we are to reconcile with others. In that we are to do our part, and leave the rest up to the other party to respond. But forgiveness is always possible under the cross. It can always happen because Jesus made it possible.
The supernatural nature of forgiveness is simply amazing. I was hurt by a sister in a former church and pursued by her through abusive phone calls, psychological manipulation and political maneuvering to force me to leave that church. Imagine how that hurt me - because of that hurt every time I was reminded of church, of the bible, prayer or God I felt hurt and couldn't have anything to do with it. To me it was the worst torture because when I am in trouble those are the places I'd normally go.
I was angry and felt cheated and that the injustice was against me because I was out of that church while she continued to go there.
I eventually reached the place where I had to come before God and say that I was willing to forgive her. I was so shot emotionally that I told God I was willing but I just couldn't because I didn't have the strength. I said to God that I chose not to hold anything against her, chose to bless her. I felt really shot after tha prayer, tired spiritually.
Amazingly, the next day I went to work and it dawned on me that for the first time in months I was smiling, and that the burden and weight of unforgiveness was lifted. I was able not only to read my bible and pray but it felt as fresh as when I first became a christian. The bible I could read like my favourite comic book, and prayer was something I could do for hours. My whole demeanor changed and I knew that this could only come through God's supernatural power. You just don't find healing like that overnight.
It has not been the only time I've had to forgive for something that happened to me in the church; I've had to survive a church split later on. That time the forgiveness took more time, was lingering and the key to that was being convinced by scripture that forgiveness, once one has chosen to do it, it is done, and that any time the echoes of that past come back I need to respond with the word as Jesus did in the desert. Satan loves to convince us otherwise, but once the forgiveness has been made the sting of that goes.
Your father may never repent, never even acknowledge what he has done, never stop doing what he has done. But it's not about him. By not forgiving him in your heart you are allowing him to have a hold on your life, have power over your very way of living. And it should not be. Jesus forgave you for your lifetime of sin against God; he can empower you to forgive your father if you are willing and say so to God, asking for that power to do so.
And I promise you, if you are able to release that to God, you will be healed and you will have grown a great deal in your understanding of what it meant for Jesus to forgive you.
