Kāsib.
Someone said that he was Yaʿqūb al-Dawraqī, but that is unlikely. I am not certain that al-Dawraqī ever heard from Ibrāhīm ibn Saʿd, though it is conceivable. As for the view that he was Yaʿqūb ibn Ibrāhīm ibn Saʿd, that is incorrect, for al-Bukhārī did not live long enough to meet him. Some have further suggested that he might be Yaʿqūb ibn Muḥammad al-Zuhrī al-Madanī, who is counted among the weak transmitters. Ibn Kāsib died toward the end of 241 AH.
64 – Muḥammad ibn Abī al-Sarī Mutawakkil al-ʿAsqalānī * (D)
A ḥāfiẓ, scholar, and truthful narrator, Abū ʿAbd Allāh ibn Mutawakkil al-ʿAsqalānī. He studied under Fuḍayl, Muʿtamir ibn Sulaymān, Rishdīn ibn Saʿd, Ibn ʿUyaynah, Ibn Wahb, Zayd ibn Abī al-Zarqāʾ, ʿAbd al-Razzāq, and many others. Those who transmitted from him include Abū Dāwūd, Bakr ibn Sahl, al-Ḥasan ibn Sufyān, ʿAlī ibn Muḥammad al-Ḥakkānī, Muḥammad ibn al-Ḥasan ibn Qutaybah, Jaʿfar al-Firyābī, and a host of others. He was the leading ḥadīth scholar of Palestine. Yaḥyā ibn Maʿīn deemed him trustworthy. Ibn Ḥibbān said, “He was among the ḥuffāẓ,” whereas Ibn ʿAdī noted, “He made many mistakes.” I say: he was one of the great repositories of ḥadīth. He died in 238 AH. He was the brother of al-Ḥusayn ibn Abī al-Sarī.