As for the other companions of the Holy Prophet...

As for the other companions of the Holy Prophet, their sayings which have come down to us do not contain enough material on this subject. The majority of the mystics and gnostics, whether Sunni or Shi'ah consider the chain of their spiritual leaders going to Imam Ali through such companions of his as Salman Farsi, Uways Qarani, Kumayl bin Ziyad, Rashid Hujari, Mitham Tammar, Rabi’ bin Khaytham and Hasan Basri.

Next to this group some other persons like Taus Yamani, Shayban Ra'i, Malik ibn Dinar, Ibrahim bin Adham and Sharif Balkhi appeared in the second century, they were considered holy men by the people. These persons were apparently ascetics. They did not talk openly of gnosis or mysticism, though they conceded that they were introduced to spiritualism by the first group and trained by it.

Towards the end of the second century and the beginning of the third some other individuals like Bayazid Bistami, Ma'ruf Karkhi and Junayd Baghdadi appeared. They openly talked of gnosis. Some of their esoteric sayings based on their spiritual intuition were apparently so obnoxious that they were strongly denounced and condemned by some jurists and theologians.

Consequently several of these gnostics were imprisoned and flogged and a few of them were even put to death.[^4] Nevertheless this group continued to flourish and maintained its activities despite all opposition. Thus the development of gnosis or mysticism continued till this system reached the zenith of its popularity and expansion in the seventh and the eighth centuries.

During the later periods its popularity fluctuated from time to time, but it has been able to maintain its existence in the Islamic world till today.

It appears that most of the mystic leaders whose names are found in biographies and memoirs belonged to the Sunni school of thought and the current Sufi system that comprises some ceremonials and rituals not consistent with the teachings of the Qur'an and Sunnah, is the heritage transmitted by these gnostics and mystics, although their system has subsequently adopted a few Shi'ah rites also. Some spiritual leaders hold that no mystic or gnostic system or program was prescribed by Islam.

The present gnostic system was invented by the mystics themselves; yet it has the approbation of Allah in the same way as monasticism was sanctioned by Allah after it had been introduced by the Christians into their religion with a view to propagate Christianity.