Grading: This hadith is "hasan".
Technical note / Defect ('illah): There is no harm in the narrators apart from the author's shaykh, and he is corroborated. Abu Kathir, the freed slave (mawla) of Muhammad bin 'Abd Allah bin Jahsh, is described sometimes as the mawla of the Asadis and sometimes as the mawla of the Laythis; a number of people narrated from him and Ibn Hibban mentioned him in "al-Thiqat" (5/ 570), so someone like him is "hasan al-hadith", if Allah wills. However, there is a disagreement over him in this narration, as explained in "Musnad Ahmad" (37/ 22494). al-'Ala' bin 'Abd al-Rahman is Ibn Ya'qub al-Huraqi.

Reference / Source: Ya'qub bin Sufyan narrated it in "al-Ma'rifah wa-l-Tarikh" (1/ 306) (and via him al-Bayhaqi 2/ 228), and al-Tabarani in "al-Kabir" (19/ 550) (and via him Abu Nu'aym in "al-Sahabah" (628)) from Yahya bin Ayyub al-'Allaf; both of them (Ya'qub and Yahya al-'Allaf) from Sa'id bin Abi Maryam, with this same chain.

Reference / Source: Abu Nu'aym narrated it (629) via Khalid bin Makhlad al-Qatawani, from Muhammad bin Ja'far; and Imam Ahmad (22494) via Hafs bin Maysarah, from al-'Ala'. See the rest of its takhrij there.

Note / Clarification: This narration will come again later at number (7548) via Isma'il bin Ja'far (the brother of Muhammad bin Ja'far), from al-'Ala' bin 'Abd al-Rahman, and there the author mentioned the other hadiths of this chapter, so see them.

Verification of names: Our manuscripts have "Abu", and we have entered it according to the Mahmudiyyah manuscript, as in the al-Maiman edition. There is a disagreement about the lineage of this "Yazid"; al-Mizzi said in "Tahdhib al-Kamal" (32/ 141): Yazid bin Sa'id bin Thumamah bin al-Aswad bin 'Abd Allah bin al-Harith al-Kindi, the father of al-Sa'ib bin Yazid; and other things have been said about his lineage.