Source of Sufism
9-1-2002 | IslamWeb
Question:
I am from Ahlu al-Sunnah wal Jamaah, al-Hamdulillah, wa li'llaahi al-hamd. As I have been taught and educated (about Islam) that in my belief there is no Sufism in true Islam. I have read that Sufism was brought and introduced to Muslim Countries by some deviating Muslims who were highly influenced and affected by Indian mysticism. Sufi terminology is neither mentioned in holy Qur'an nor in authentic Sunnah, so, where it did come from? Please, give Islamic ruling for this issue.
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
We ask Allah to make us and you stick to right belief and the right religion applied by Ahlus-Sunnah wal Jamaa’ah. As for Sufism and its origins and whether Sufis are innovators or not, Muslim scholars have thoroughly discussed this issue.
Shaykh Ibn Taymiyyah 
did some good research on this subject and said: “As for the word ‘Sufism’, it was not known in the first three centuries of Islam. It actually became famous after that period. It is reported that some eminent scholars like Imam Ahmad Ibn Hanbal and Ad-Darany and others talked about Sufism. It is known that this word derives from the Arabic word "Sufi" which literally means "wool". So, the first people called "Sufis" were known to wear woolen garments. Sufism first appeared in Basra. The Sufis in Basra were very modest and lived an ascetic life. They were so devout they were known to occupy themselves with all forms of worship and to fear Allah very much. So, their devout way was not known anywhere else in the Muslim world.”
Ibn Taymiyyah added: “And because of their unfamiliar way, people had different opinions about them. Some praised them (saying Sufis were very devout), while others criticized them for being too ascetic. The latter said that Sufis were innovators, very far from the Sunnis way.”
A group of scholars and Muslim jurists were of this last opinion. Some people, however, claimed that Sufis were the best people after the Prophets. Both groups were wrong in their assessment of Sufis.
The correct opinion is that they used to work hard in worshipping Allah as the other righteous people used to do. So, among them some were foremost in good deeds (by virtue of their good deeds); some of them followed a middle course of those who will be given their record in their right hand. However, among both categories, surely there are some who commit mistakes in their Ijtihad, those who commit sins and then repent to Allah, and also others who commit sin and do not repent.
Some innovators joined the Sufis and some of them even went astray. But some Sufi scholars claim that those innovators and perverted people who called themselves Sufis were not among Sufis. They say that Al-Hallaj, for instance, was not a Sufi but a Zindeeq (a heretic). Ibn Taymiyyah goes on by saying: “This was the origin of Sufism. Then it became much more diverse and complicated.”
This diversity and complication brought many more deviated Sufi groups. Some of them based their ideas on Indian mysticism. Others chose Persian, Greek or idolaters' philosophies and followed them claiming they were Islamic.
To conclude, the way to safety from all innovations is to learn the right Aqeeda (creed); i.e. the creed of Ahlus-Sunnah wal Jamaah. So, when a person knows the truth, he will know the people who apply it in their lives.
For more benefit on Sufism, please refer to Fataawa 82017, 31043, 31031, and 29243.
Allah knows best.