The word "Tasawwuf" (the Arabic word for "Sufism") was used by the Prophet (Peace Be Upon Him), he certainly used the word 'Ihsan' or spiritual sincerity. Sufi Shaykhs have said that Sufism itself is nothing other than this sincerity, or the perfect following of the way of Hazrat Mohammad (SM) (PBUH), both inner and outer as well as Ahle-Bayet (Family members of Great Prophet). Therefore, Tasawwuf, or Sufism, can in no way be divorced from the teachings of the Prophet Mohammad (Peace Be Upon Him). Anyone who acts contrary to the principles of Islam cannot be considered a Sufi, in spite of their claims. Care must be taken when choosing a guide, for as Hasan al Basri, a Shaykh of the the 7th century said, "Association with the wicked produces suspicion of the good". After the departure of the Prophet Hazrat Mohammad (Peace Be Upon Him) (SM) from this world to heaven in 632 A.D., 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 Shaykhs, for the generation after them. This process has continued down to our present time by the Mercy of Allah. In this way, every authentic Sufi guide has a chain of teachers which leads directly back to the Prophet Mohammad (SM) (Peace Be Upon Him). The Fourth Caliph of Islam Hazrat Ali Ibn Abu Talib (PBUH), is the Grand Sufi Master of all Sufis. He is also the Supreme Authority of Sufism. Such a chain of teachers is known in Sufism as a "Silsilah" or a "Shajarah" (Sufi Order).
In the English language, each of these "tariqahs" is known as a 'Sufi Order'. Starting from Hazrat Ali (PBUH) the Sufism spread thru the following list of Imams who are direct descendants of Prophet Hazrat Mohammad (SM) (PBUH) thru Hazrat Fatima (PBUH) and Hazrat Ali (PBUH), Hazrat Hasan (PBUH) and Hazrat Hussein (PBUH).
Ø Hazrat Ali ibn Abu Talib al Murtadha (PBUH) The First Imam and Father of Imams
Ø Hazrat Hasan ibn Ali al Mujtaba (PBUH) The Second Imam
Ø Hazrat Hussein ibn Ali al Shaheed (PBUH) The Third Imam
Ø Hazrat Ali ibn Husayn al Zayn‐al‐Abedin (PBUH) The Fourth Imam
THE LAST & FINAL IMAM HAZRAT IMAM MAHDI (PBUH) WILL LEAD THE HUMANITY TO CO-CREATE HEAVEN ON EARTH ALONG WITH HAZRAT ISA (PBUH) VERY SOON.
Often, one of the Shaykhs may be so prominent, or become so well-known, that his students will identify themselves by saying they follow the way of such-and-such a Shaykh. The Arabic word for way is 'tariqah' (Spiritual Guide/Guardian). So for example, students of the great Shaykh, Hazrat Bahauddin Naqshband (RA) founder of Naqshband sufi order, and his successors down to the present day are said to follow the Naqshbandi tariqah. Similarly, Hazrat Abdul Qadir Jilani (RA) founder of Qaderia Sufi order, Hazrat Khawja Moinuddin Chishti (RA) founder of Chistia Sufi Order (tariqah), and Hazrat Abul Hasan Shadhili to the Shadhili tariqah, and Hazrat Ahmed Faruqi Sirhindi Mujadded Alfe-Sani, founder of the Mujaddedi tariqah. Ultimately, all of these orders lead directly back to the Prophet Mohammad (Peace Be Upon Him), and their differences are mostly geographical and superficial.