Sufism or tasawwuf (Arabic تصوف) is mystical and ascetic branch of Islam and one of the main in classical Islamic philosophy. There are several hypotheses for the origin of the words tasawwuf and Sufi. Common is the view expressed even medieval Muslim authors, according to the word Sufi comes from the Arabic “suf” (Arabic صوف - wool) It has long been a rough woolen garment was common attribute of ascetics and hermits, “God's people” and mystics. Sufis often erect its etymology to the root of the word “safa” (purity), “Sifat” (property) or to the expression “Ahl al-Suffa” (“people of the bench, or overhang”), which has been used in relation to the poor companions of the Prophet Muhammad, who lived in his mosque in Medina, and is distinguished by its austerity. Sufism has developed within Islam, almost nothing take from Muslim sources, but absorbed the experience mystical and ascetic practices and philosophy of Eastern Christianity. Sufism regardless of the volume of borrowings from neo-Platonism, Gnosticism, Christian mysticism or from other systems, we can consider the as “inner-Islam doctrine, mystery underlying the Koran”.