 Luther would fast for days on end without a crumb of food, is how he would describe it. He would throw off the blankets from his bed in the dead of the German winter and freeze himself to death or half to death. Later in life, this is something that Luther said. I'm quoting him now. I was a good monk, and I kept the rule of my order so strictly that I may say that if ever a monk got to heaven by his monkery, it was I.