Forgiveness is an act of will and the will can function regardless of the temperature of the heart.
The experiences of our lives, when we let God use them, become the mysterious and perfect preparation for the work he will give us to do.
Even as the angry vengeful thoughts boiled through me, I saw the sin of them. Jesus Christ had died for this man, was I going to ask for more? Lord Jesus, I prayed, forgive me and help me to forgive him... Jesus I cannot forgive him. Give me your forgiveness...and so I discovered that it is not on our forgiveness any more than on our goodness that the world's healing hinges, but on his. When he tells us to love our enemies, he gives along with the command, the love itself.