"Sufi" is from the Arabic word "suf" which means "wool". This word is dervied from the "Ahl-e-Sufa" or Ashab-e-Sufa (literally, 'The People of the Bench'), a group of early muslims who migrated from Makka to Madina, and lived in the first mosque at Madina (Masjid-e-Nabwi) in close proximity to Prophet (peace be upon him). They remained busy in worship, meditation & Zikr, all the time. They preferred the spiritual side of life than the materialism. It is said that the total number of Ashab-e-Sufa was about 80. The Holy Prophet took especial care of them.

After the departure of the Prophet Mohammad (peace be upon him) from this world, those who were closest to him passed on his teachings to the sincere seekers of the next generation, who in turn became the perfected guides, or Shaikhs, for the generation after them. This process has continued down to our present time by the Mercy of Allah. Such a chain of teachers is known in Sufism as a "Silsilah"(Sufi Order). There are more than 250 Sufi Orders or Silsilah till now.

The word "Sufi" was not publically known during the life time of the Holy Prophet Mohammad (only the word "Ahl Sufa" was known), but in fact Prophet Mohammad & few of his Companions hinted about the existence of Sufis during the life time of Prophet Mohammad.  For example, Hazrat Salman Farsi and Abu Zar Ghaffari did not have the same degree of faith. The degree of faith which Hazrat Salman Farsi had, was unbearable to Hazrat Abu Zar Ghaffari. Several traditions (Hadiths) say: "If Abu Zar Ghaffari had known what was in Salman Farsi's heart, he would have killed him (thinking him to be an infidel). That Hadith clearly shows that Prophet Mohamamd was himself well aware of the gnosis of his Companions. Hazrat Salman Farsi also lived in the desert for many years like a Dervish, he came back to Madina in the caliphate of Hazrat Usman Ghani.

Hazrat Abu Hurayra, who narrated most of the Hadiths, once said to the other Companions: "From the Apostle of Allah, I've learned two kind of knowledge, the first kind I've disclosed to you people (i.e. Hadith)" The Companions asked that why he didn't disclose the second kind of knowledge? Hazrat Abu Hurayra replied: "If I would disclose that kind of knowledge to you, you would cut my throat."

The above Hadith of the Holy Prophet & the saying of Hazrat Abu Hurayra clearly confirm that along with Sharia't (Islamic Law), Tariqat (Sufism) was also in progress, but for some reasons they kept it secret from others.

Also, there are numerous passages in the Holy Quran which are of a mystical character. The Holy Prophet himself displayed mystical inclinations and he very often retired to the cave of Hira for the purpose of devotions, meditation and contemplation. The Holy Prophet was recipient of two types of revelations, one embodied in the Holy Quran, and the other that illuminated his heart. The former was meant for all, the latter for a selected few whose hearts could be illuminated with the Divine Light. The knowledge of the Holy Prophet was thus book knowledge (ilm-e-Safina), and heart knowledge (ilm-e-Sina).

Hazrat Ali was the most gnostic Companions of the Holy Prophet, and he preferred inner or spiritual knowledge than the outer knowledge, that's why about him the Holy Prophet said: "I am the city of knowledge, and Ali is the gate." Once Hazrat Ali said: "I know God by God." And when some one asked him whether he had seen God? Hazrat Ali said: "Verily I have seen God, for I could not worship Him unless I know Him."