The institution of Theosophy (Tasavvuf) is ancient. It has been practised by the Prophets and the Saints. As evil impulses predominate in the world, the Theosophist (Sûfî) is looked down upon by men. The Theosophist is one who has lost the self, exists in the True One, is beyond the reach of the lower nature, and is at one with Truth. A Theosophical student (mutasavvif) is he who seeks to become a Theosophist through asceticism and purification, and disciplines himself in the ways of the Theosophist …
The Prophet had a place in his mosque set apart to discourse privately with his elect companions, who trod the Path. There were senior disciples such as Abubakar, Omar, Osman, Alî and Salmân; and mediocre ones, such as Belal and others. The Arab chiefs and his ordinary companions were not admitted there. The elect companions were about 70 in number. When the Prophet wished to shew his special regard to a particular companion (Sûfî), he favoured him with a piece of his garment (N. B. The word Sûfî may be derived either from Safâ, purity, or from Sûf, dress.—Trs.)
The first Theosophist was Adam, and the last Mohammad; and Theosophy has continued amongst the followers of Mohammad.—Letter 22.