Ibn Khaldun said in his famous Muqaddima:
The foundation of the way of the Sufis is self-restraint in the world and utter dependence on Allah; shunning of the adornment and beauty of the world; self-deprivation of pleasure, money, and title in the manner agreed upon by the vast majority of the scholars; and isolation from creatures in seclusion and devotion to worship.
All these aspects were widespread among the Companions and the Salaf, but with the pervasiveness of worldliness in the second century and the next, and the general inclination of the people towards the world, those who remained attached to worship became know under the name of Sufis.1
1 Muqaddimat ibn Khaldun, p. 328.Reproduced
with permission from Shaykh M. Hisham Kabbani's
The Repudiation of "Salafi" Innovations (Kazi, 1996) p. 382.
Blessings and Peace on the Prophet, his Family, and his CompanionsAbu Hammad