" You could cut down a tree with your axe,” Raen said. “The axe does violence to the tree, and escapes unharmed. Is that how you see it? Wood is soft compared to steel, but the sharp steel is dulled as it chops, and the sap of the tree will rust and pit it. The mighty axe does violence to the helpless tree, and is harmed by it. So it is with men, though the harm is in the spirit. "

― Robert Jordan , The Eye of the World (The Wheel of Time, #1)