The critical scholar Shaykh Aḥmad Shākir, may Allah have mercy on him, said in his commentary on al-Tirmidhī (2/277):

“It appears that al-Tirmidhī is indicating a hidden defect in the hadith’s chain of transmission: the narrators related it from Isrāʾīl, from Abū Isḥāq, whereas no one related it from al-Thawrī except Abū Aḥmad. Yet this is not a defect if the narrator is trustworthy. There is no objection to the hadith having been narrated by both al-Thawrī and Isrāʾīl from Abū Isḥāq. Abū Aḥmad is trustworthy, so his narration from al-Thawrī reinforces the narration of the others from Isrāʾīl. Furthermore, like the others, he also narrated it from Isrāʾīl: he retained what they retained and added what they did not know, or what they did not transmit to us.”

I say: This is the sound conclusion required by the methodology of hadith criticism.

Nevertheless, both he and al-Tirmidhī need to be corrected in light of the aforementioned narration of ʿAbd al-Razzāq from Sufyān al-Thawrī. This supports Aḥmad Shākir’s conclusion, may Allah have mercy on him.

He also omitted tracing the hadith of Isrāʾīl from Abū Isḥāq—the second of his three students previously mentioned. I therefore say:

Second: Isrāʾīl—son of Yūnus ibn Abū Isḥāq al-Sabīʿī—narrated it from Abū Isḥāq, including the additional wording.

It was recorded by Aḥmad (2/24, 58, 77, and 99), and al-Ṭaḥāwī in Sharḥ al-Maʿānī (1/176), through several routes from him. One of them, in Aḥmad’s third cited location, is through Muḥammad ibn ʿAbd Allāh ibn al-Zubayr, namely Abū Aḥmad al-Zubayrī, who narrated to us.

Third: Abū al-Aḥwaṣ Sallām ibn Sulaym narrated it from Abū Isḥāq, including the additional wording:

“I heard the Prophet (peace and blessings be upon him) recite more than twenty times …” to the end of the hadith.