that Muḥammad ibn Ubayy ibn Kaʿb—as he appears in the chain of transmission—was not Ubayy’s son, but his grandson.

This is supported by the narration of Abū Dāwūd al-Ṭayālisī, who said: “Ḥarb ibn Shaddād narrated to us,” with the same chain, except that he said: “from Muḥammad ibn ʿAmr ibn Ubayy ibn Kaʿb, from his grandfather Ubayy ibn Kaʿb, who had a date storehouse ...” Thus, he agreed with him regarding the grandfather and added to it by naming Muḥammad’s father as ʿAmr.

Al-Ḥākim recorded it (1/561–562), and al-Bayhaqī transmitted it through his route (7/109).

Abān ibn Yazīd differed from Ḥarb, narrating: from Yaḥyā ibn Abī Kathīr, from al-Ḥaḍramī ibn Lāḥiq, from Muḥammad ibn Ubayy ibn Kaʿb, from his father: “He had a date storehouse ...”

Al-Ṭabarānī recorded it (1/169/541). Al-Mundhirī said (1/232): “Its chain of transmission is sound.”

Imām al-Bukhārī mentioned these two differing versions in the biographical entry for Muḥammad ibn Ubayy ibn Kaʿb in al-Tārīkh (1/1/27). He also mentioned the previously cited narration of al-Walīd ibn Muslim from al-Awzāʿī, in which the name of Ibn Ubayy ibn Kaʿb is left unspecified.

This is a serious discrepancy, before which the researcher stands perplexed and unable to reach a definite conclusion.

Yet, if I must express my view, I consider the narration stating, “Muḥammad ibn Ubayy ibn Kaʿb: ‘My grandfather had ...’” to be stronger, because it agrees with the narration of al-Ṭayālisī, which makes Ubayy ibn Kaʿb the grandfather of Muḥammad ibn Ubayy ibn Kaʿb. The only difference is that it names the son of Ubayy ibn Kaʿb as ʿAmr. This is an addition from a trustworthy narrator—indeed, a hadith master—namely Imām al-Ṭayālisī, the author of al-Musnad; and an addition from a trustworthy narrator is accepted, as is well known.

This is my view. However, I have not found any of the early hadith masters who gave it serious consideration, such as al-Mizzī and al-ʿAsqalānī. In their respective works entitled al-Tahdhīb, they included a biographical entry only for Muḥammad ibn Ubayy ibn Kaʿb, since he is the one named by al-Nasāʾī, rather than Muḥammad ibn ʿAmr ibn Ubayy, as mentioned above. They said: