As it was more easy to learn their doctrine than to practise it, I studied first of all those of their books which contain it: "The Nourishment of Hearts," by Abu Talib of Mecca, the works of Hareth el Muhasibi, and the fragments which still remain of Junaid, Shibli, Abu Yezid Bustami, and other leaders (whose souls may God sanctify). I acquired a thorough knowledge of their researches, and I learned all that was possible to learn of their methods by study and oral teaching. It became clear to me that the last stage could not be reached by mere instruction, but only by transport, ecstasy, and the transformation of the moral being. To define health and satiety, to penetrate their causes and conditions, is quite another thing from being well and satisfied. To define drunkenness, to know that it is caused by vapors which rise from the stomach and cloud the seat of intelligence, is quite a different thing to being drunk. The drunken man has no idea of the nature of drunkenness, just because he is drunk and not in a condition to understand anything, while the doctor, not being under the influence of drunkenness, knows its character and laws. Or if the doctor fall ill, he has a theoretical knowledge of the health of which he is deprived. In the same way there is a considerable difference between knowing renouncement, comprehending its conditions and causes, and practising renouncement and detachment from the things of this world. I saw that Sufism consists in experiences rather than in definitions, and that what I was lacking belonged to the domain, not of instruction, but of ecstasy and initiation. The researches to which I had devoted myself, the path which I had traversed in studying religious and speculative branches of knowledge, had given me a firm faith in three things—God, Inspiration, and the Last Judgment. These three fundamental articles of belief were confirmed in me, not merely by definite arguments, but by a chain of causes, circumstances, and proofs which it is impossible to recount. I saw that one can only hope for salvation by devotion and the conquest of one's passions, a procedure which presupposes renouncement and detachment from this world of falsehood in order to turn toward eternity and meditation on God. Finally, I saw that the only condition of success was to sacrifice honors and riches and to sever the ties and attachments of worldly life.