I say: The men in this chain are all reliable and well-known, except for this Abū Yaʿqūb. ʿAbd al-Wāḥid ibn Ziyād called him “ʿAbd Allāh” and stated— as you have seen— that he was his grandfather. I have been unable to identify him; the biographical works omit him entirely, mentioning him neither under kunyahs nor under personal names.

It occurs to me that he might be ʿAbd Allāh ibn ʿAbd Allāh ibn al-Aṣam, for the authorities list among his transmitters both ʿAbd al-Wāḥid ibn Ziyād and Marwān al-Fazārī—the very two who, as you can see, narrated this ḥadīth from him. What makes this identification difficult is that they do not report that he bore the kunyah Abū Yaʿqūb; instead they give him two other kunyahs, Abū Sulaymān and Abū al-ʿAnbas.

Another possibility is that the kunyah Abū Yaʿqūb is a scribal corruption of Abū Yaʿfūr, whose name is ʿAbd al-Raḥmān ibn ʿUbayd ibn Nustās al-Kūfī. This man narrated from Abū Thābit Ayman ibn Thābit, and from him Marwān al-Fazārī took the report, as recorded in al-Tahdhīb. If that is indeed the case, he is trustworthy and numbered among the narrators of the two Shaykhs (al-Bukhārī and Muslim), and the chain would therefore be sound. The objection, however, is that ʿAbd al-Wāḥid ibn Ziyād called him “ʿAbd Allāh, my grandfather”; one could say that this phrase in ʿAbd al-Wāḥid’s version is an interpolation inserted by a copyist of the Musnad.

In sum, this chain remains problematic in my view, and perhaps we shall later come across something that brings the correct conclusion to light. Allah’s help is sought.

It was likely for this very reason that al-Mundhirī kept silent about this chain in at-Targhīb (3/54), and al-Haythamī followed suit (4/175), attributing the report to al-Ṭabarānī as well.