"I am David Monroe, who fought Voldemort," the man said, still in mild tones. "Heed my words. The boy cannot be allowed to continue in this state of mind. He will become dangerous. It is possible that you have already done everything you can. Yet I find this a very rare event indeed, and more often said than done. I suspect rather that you have only done what you customarily do. I cannot truly comprehend what drives others to break their bounds, since I never had them. People remain surprisingly passive when faced with the prospect of death. Fear of public ridicule or losing one's livelihood is more likely to drive men to extremes and the breaking of their customary habits. On the other side of the war, the Dark Lord had excellent results from the Cruciatus Curse, judiciously used on Marked servants who cannot escape punishment except by success, with no reasonable efforts accepted. Imagine their state of mind within yourself, and ask yourself whether you have truly done all that you can to wrench Harry Potter from his course."