But at the same time some of them were destined that they could not guide and serve the world best unless they were ascetics. In that case it was necessary for them to be so. Sufism therefore does not urge asceticism except as a prescription, just as these ten vows have been given. That is a lesson in asceticism in a small way. Each person has to keep a certain principle every day. That is asceticism. One need not go in a cave to be an ascetic. One can live a life of principle; that is asceticism: if not more, less, but still a lesson of asceticism.