Sufism consists essentially in giving up oneself constantly to devotional exercises, in living solely for God, in abandoning all the frivolous attractions of the world, in disregarding the ordinary aims of men--pleasures, riches and honours--and finally in separating oneself from society for the sake of practising devotion to God. This way of life was extremely common among the companions of the Prophet and the early Moslems. But when in the second century of Islam and the succeeding centuries the desire for worldly wealth had spread, and ordinary men allowed themselves to be drawn into the current of a dissipated and worldly life, the persons who gave themselves up to piety were distinguished by the name of "Sufis," or aspirants to Sufism. The most probable derivation is from "suf" (wool), for, as a rule, Sufis wear woollen garments to distinguish themselves from the crowd, who love gaudy attire. For an intelligent being possessed of a body, thought is the joint product of the perception of events which happen from without, and of the emotions to which they give rise within, and is that quality which distinguishes man from animals. These emotions proceed one from another; just as knowledge is born of arguments, joy and sadness spring from the perception of that which causes grief or pleasure. Similarly with the disciple of the spiritual life in the warfare which he wages with himself, and in his devotional exercises. Every struggle which he has with his passions produces in him a state resulting from this struggle. This state is either a disposition to piety which, strengthening by repetition, becomes for him a "station" (_maqam_), or merely an emotion which he undergoes, such as joy, merriment, &c. The disciple of the spiritual life continues to rise from one station to another, till he arrives at the knowledge of the Divine Unity and of God, the necessary condition for obtaining felicity, conformably to the saying of the Prophet: "Whosoever dies while confessing that there is no god but God, shall enter Paradise." Progress through these different stages is gradual. They have as their common foundation obedience and sincerity of intention; faith precedes and accompanies them, and from them proceed the emotions and qualities, the transient and permanent modifications of the soul; these emotions and qualities go on producing others in a perpetual progression which finally arrives at the station of the knowledge of the Unity of God. The disciple of the spiritual life needs to demand an account of his soul in all its actions, and to keep an attentive eye on the most hidden recesses of his heart; for actions must necessarily produce results, and whatever evil is in results betokens a corresponding evil in actions.