“Muḥammad ibn Ubayy ibn Kaʿb al-Anṣārī, Abū Muʿādh, the Medinan; and it is also said: Muḥammad ibn So-and-so ibn Ubayy ...”

Thus, by their use of “So-and-so,” they indicated ʿAmr, and that inserting his name between Muḥammad and Ubayy ibn Kaʿb is incorrect. Their basis for this—Allah knows best—is the statement of Abū Ḥātim in the biographical notice for Muḥammad ibn Ubayy in al-Jarḥ (3/2/208):

“He narrated from his father. Busr ibn Saʿīd, al-Ḥaḍramī ibn Lāḥiq, and his son Muʿādh ibn Muḥammad narrated from him. Al-Bukhārī treated him as two separate persons. I heard my father say: ‘They are one and the same.’ Al-Awzāʿī narrated from Yaḥyā ibn Abī Kathīr, from him; and Ḥarb ibn Shaddād narrated from Yaḥyā ibn Abī Kathīr, from al-Ḥaḍramī ibn Lāḥiq, from him.”

What is also noteworthy is the discrepancy between al-Mizzī’s Tahdhīb and al-ʿAsqalānī’s Tahdhīb. The former said: “He narrated from his grandfather!” He then reports from al-Wāqidī that Muḥammad ibn Ubayy ibn Kaʿb was among those killed on the Day of al-Ḥarrah in the year 63 AH. Perhaps his statement, “from his grandfather,” was a scribal error.

Another point is that Abū Ḥātim, who objected to al-Bukhārī’s treating the name as two separate persons and decisively held that they were one and the same, nevertheless provided a separate biographical notice for Muḥammad ibn ʿAmr ibn Ubayy ibn Kaʿb al-Anṣārī, saying:

“He narrated from Umm al-Ṭufayl, the wife of Ubayy ibn Kaʿb. Muḥammad ibn ʿAbd al-Raḥmān ibn Saʿd ibn Zurārah narrated from him.”

Al-Bukhārī had preceded him in this (1/1/192), and Ibn Ḥibbān followed them, mentioning him in al-Thiqāt on the basis of this narration.