Her teaching focused on the Christian Gospel, with emphasis on forgiveness. In her book Tramp for the Lord (1974), she tells the story of an encounter while she was teaching in Germany in 1947. She was approached by a former Ravensbrück camp guard, who had been known as one of the most cruel. She was reluctant to forgive him, but prayed that she would be able to. Ten Boom wrote: For a long moment we grasped each other's hands, the former guard and the former prisoner. I had never known God's love so intensely as I did then.