Here is an excerpt from her biography, The Hiding Place ~
Some years later, Corrie gave a speech at church in Numich, after which a heavyset man approached her. Corrie recognized him as one of the most brutal guards in her camp. She froze in pain and anguish. The man said to her, “Since that time, I have become a Christian. I know that God has forgiven me for the cruel things I did there, but I would like to hear it from your lips as well. Fraulein – will you forgive me?” Corrie wrestled with what she said. It was the most difficult thing she ever did. She wrote,
I had to do it – I knew that. The message that God forgives has a prior condition: that we forgive those who have injured us. “Jesus, help me!” I prayed silently. “I can lift my hand. I can do that much. You supply the feeling.”
And so woodenly, mechanically, I thrust my hand into the one stretched out to me. And as I did, an incredible thing took place. The current started in my shoulder, raced down my arm, sprang into our joined hands. And then this healing warmth seemed to flood my whole being, bringing tears to my eyes.
“I forgive you, brother!” I cried. “With all my heart!”
For a long moment we grasped each other’s hands, the former guard and the former prisoner. I had never know God’s love so intensely as I did then.
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.