It is all right for a man who goes into a mountain cave or into the forest and says that he does not care to develop either his character or his personality; it is just as well that he should go there and not take the trouble to develop his nature. He need not change, he need not worry, he can live just like the trees and plants in nature which just grow; they do not develop themselves. But if he has to live in the midst of the crowd in this artificial world, then he must know the art of developing the character, and how to produce beauty in life. Among all the different schools of esotericism and mysticism the Sufi school has concerned itself most with the development of personality.