Qutaybah said, “Had Muhammad been among the Companions, he would have been a sign in himself.” (1)

Muhammad ibn Yusuf al-Hamadhani related: “We were with Qutaybah ibn Saʿid when a shaggy-haired man called Abu Yaʿqub arrived and asked him about Muhammad ibn Ismaʿil. Qutaybah lowered his head, then raised it toward the sky and said, ‘My friends, I have examined hadith, reflected on juristic opinion, and sat with jurists, ascetics, and devoted worshippers. Since I reached understanding, I have never seen anyone comparable to Muhammad ibn Ismaʿil.’” (2)

Hashid ibn Ismaʿil said: “I heard Qutaybah declare, ‘The standing of Muhammad ibn Ismaʿil among his contemporaries, in truthfulness and scrupulous piety, is like the standing of ʿUmar among the Companions.’” (3)

Hashid ibn Ismaʿil also reported: “I heard Ahmad ibn Hanbal say, ‘No one has ever come to us from Khurasan like Muhammad ibn Ismaʿil.’”

We have likewise transmitted from Abu Hatim al-Razi, who said, “Muhammad ibn Ismaʿil was the most knowledgeable person to have entered Iraq.”

Abu ʿAbd Allah al-Hakim said, “Muhammad ibn Ismaʿil al-Bukhari is the imam of the people of hadith. In Bukhara he listened to Harun ibn al-Ashʿath, Muhammad ibn Salam, and many other teachers whose names he himself listed.”

He further reported: “I heard Abu al-Tayyib Muhammad ibn Ahmad al-Mudhakkir say that he heard Abu Bakr Muhammad ibn Ishaq ibn Khuzaymah state, ‘Beneath the entire span of heaven I have never seen anyone more learned in the hadith of the Messenger of Allah, peace and blessings be upon him, nor one with a better memory for it, than Muhammad ibn Ismaʿil.’”