There is a common misconception that Sufism is a sect of Islam. Actually, Sufism can be more accurately described as an aspect or dimension of Islam. Ibn Khaldun, a 14th century Arab historian described Sufism as “dedication to worship, total dedication to Allah most high, disregard for the finery and ornament of the world, abstinence from the pleasure, wealth, and prestige sought by most men, and retiring from others to worship alone.”
Khaldun’s description of Sufism still holds true over 700 years later. Sufi’s believe that Islamic knowledge not only has to be learned from books, but that teachers play an important role. The teachers of Islam date all the way back to the Prophet, with current day students trying to absorb what character they can of the Prophet. Sufi’s are responsible with spreading Islam to the furthest outposts of the Muslim world, including Africa, India, and the Far East.
Sufi’s find their purpose in life from a verse in the Quran, “I created the Jinns and humankind only that they may worship me.” Sufi’s belong to Tariqas, or orders, to pursue their goal of worshipping Allah. The Tariqas were established a few centuries after Allah’s death, they are orders which have a master who teaches the sacred knowledge of Islam to their students.
Source: https://www.bbc.co.uk/religion/religions/islam/subdivisions/sufism_1.shtml