Shuba expressed uncertainty in narrating from the Prophet ﷺ that he said, "Whoever I am his master, Ali is his master."
حدثنا محمد بن بشار حدثنا محمد بن جعفر حدثنا شعبة عن سلمة بن كهيل قال سمعت أبا الطفيل يحدث
شك شعبة عن النبي ﷺ قال من كنت مولاه فعلي مولاه
No references are available.
[Its chain of transmission is sahih]. Ahmad narrated it in Fadail al-Sahabah, 2/569, no. 959, from Muhammad bin Jafar through the same route. It is a mutawatir hadith, as noted in the books on mutawatir hadiths, the book of Suyuti, no. 100, Kinani, no. 232, and Zubaydi, no. 69.The hadith of Shubah, narrated by Ahmad, 4/372, in his Musnad. Nasai also narrated it in Sunan al-Kubra, no. 8148, from the hadith of Abu Tufayl through the same route, at length.