Aḥmad ibn Ḥanbal said, “In the narrations that come through al-Ḥakam, Shuʿbah is more reliable than al-Aʿmash, and in general Shuʿbah’s reports are sounder than those of al-Thawri; indeed, he transmitted from thirty scholars of Kūfa whom Sufyān never met. Shuʿbah was, in this discipline, a nation unto himself.”
ʿAbd al-Salām ibn Muṭahhir said, “I have never seen anyone who pursued worship more intensely than Shuʿbah.”
Abū Nuʿaym related, “I heard Shuʿbah say, ‘I would sooner commit fornication than resort to tadlīs (1).’”
Sulaymān ibn Ḥarb said, “One day Shuʿbah narrated to us the ḥadith of ‘the truthful, the one who is believed’ (2), along with other reports like it. A man from the Qadariyya stood up and said, ‘Abū Bisṭām, will you not relate something to us as well (3)?’ So Shuʿbah cited the ḥadith of Abū Ṣāliḥ, from Abū Hurayrah, from…"}
(1) As Ibn al-Salah explains, this ruling is intended as deliberate hyperbole and deterrence. The sound position distinguishes between a mudallis (narrator who practices tadlis): if he explicitly says “I heard,” his report is accepted; if he uses an ambiguous formula, it is rejected. Both Sahih al-Bukhari and Sahih Muslim contain reports from this type of narrators—such as the two Sufyans, al-Aʿmash, Qatada, Hushaym, and others. Al-Suyuti relates in Tadrib al-Rawi that, according to al-Hakim, no leading scholar from the Hijaz, the Two Sanctuaries, Egypt, al-Awali, Khurasan, Isfahan, Fars, Khuzistan, or Transoxania is known to have engaged in tadlis; most who did so were Kufans, with a small number from Basra. As for Baghdad, no one there was accused of tadlis until Abu Bakr b. Muhammad b. Muhammad b. Muhammad b. Sulayman al-Baghandi al-Wasiti, who was the first to introduce it.
(2) Al-Bukhari, Sahih, 6:220, 262 (Book of the Beginning of Creation) and 11:417-426 (Book of Divine Decree); Muslim, Sahih, no. 2643 (opening of the Book of Divine Decree), through multiple chains from al-Aʿmash, from Zayd b. Wahb, from ʿAbd Allah b. Masʿud: “The Messenger of Allah, the truthful and trusted, told us: ‘The creation of each one of you is gathered in his mother’s womb for forty days as a drop, then for the same period as a clot, then for the same period as a morsel of flesh. The angel is then sent, breathes the soul into him, and is commanded to write four matters: his provision, his lifespan, his deeds, and whether he will be wretched or blessed. By Him besides whom there is no deity, one of you may act with the deeds of the people of Paradise until only a cubit separates him from it, yet the decree overtakes him and he acts with the deeds of the people of Hell and enters it; and one of you may act with the deeds of the people of Hell until only a cubit separates him from it, yet the decree overtakes him and he acts with the deeds of the people of Paradise and enters it.’”
(3) Tarikh al-Fasawi, 2:283, which adds the phrase: “Do not narrate to us; we, too, forget.”