Abu Hatim ibn Hibban al-Busti: He is worthy of being followed, and he was pious and had good memory.
Abu Dawud al-Sijistani: I have not seen anyone with a better memory than him, and once: We have never seen a book of his.
Ahmad ibn Hanbal: He praised him, and once: A companion of Hadith, and once: He is worthy of being followed, and he used to respect him greatly.
Ahmad ibn Shu'ayb al-Nasa'i: Trustworthy
Ibn Abi Hatim al-Razi: The trustworthy, reliable
Ibn Hajar al-'Asqalani: Trustworthy Haafiz
al-Daraqutni: Trustworthy, reliable, his narrations are accepted as evidence.
al-Dhahabi: The Haafiz
Sulaiman ibn Dawud al-Shadhkuni: He does not acknowledge anyone's memory except his.
Abd al-Baqi ibn Qani' al-Baghdadi: Righteous, trustworthy
Abd al-Rahman ibn Mahdi: He abandoned him later on.
Muhammad ibn Muslim ibn Wahb: A pillar of the religion
Yahya ibn Ma'in: He praised him