Wahiduddin's Web

Sufism is a philosophy among the religions and it is a religion among the philosophies. Among the religions it is a philosophy by reason of the Sufi's freedom of thought; among the philosophies it is a religion because of the Sufi's idealization of God, his devotion and worship. The Sufis were called Sufis by others, they did not give themselves any name. They were free from name, from label, from distinction of personality, and for this the world called them Sufi, from Saf which in Arabic means 'pure'.

[ From http://wahiduddin.net/mv2/VIIIa/VIIIa_1_2.htm]