What is the meaning of this quote by Terry Pratchett?
Give a man a fire and he's warm for the day. But set fire to him and he's warm for the rest of his life.
I think I understand the first sentence. It says that if you give somebody e.g. a torch or help set a fire with a limited quantity of wood, it will burn only for a couple of hours and then it's done.
But what does "set fire to him" mean exactly?