Al-Ḥārith ibn Abī Usāmah said: “Abū al-Naḍr, Hāshim ibn al-Qāsim al-Kinānī—of the clan of Layth, one of their own—narrated to us. He was nicknamed ‘Qayṣar’ (Caesar), and the reason for that nickname was as follows. Naṣr ibn Mālik al-Khuzaʿī, the head of Hārūn al-Rashīd’s police force, once entered the bathhouse at the time of the afternoon prayer and told the muezzin, ‘Do not give the iqāma until I come out.’

Abū al-Naḍr then came to the mosque after the adhan had been called and said to the muezzin, ‘Why have you not pronounced the iqāma?’ He replied, ‘I am waiting for Abū al-Qāsim.’ Abū al-Naḍr said, ‘Give it.’ So the muezzin gave the iqāma and they prayed. When Naṣr ibn Mālik arrived he said to the muezzin, ‘Did I not tell you not to establish the prayer until I returned?’ The muezzin answered, ‘Hāshim ibn al-Qāsim would not allow me; he told me, “Establish it.”’ Naṣr retorted, ‘That is not Hāshim; that is Qayṣar, acting like the emperor of Rome!’ The nickname stuck (1).

Al-Ḥārith added: Aḥmad ibn Ḥanbal used to say, ‘Abū al-Naḍr is our shaykh, one of those who enjoin what is right and forbid what is wrong’ (2).

Abū Bakr al-Aʿyan transmitted from Aḥmad ibn Ḥanbal that he said, ‘Abū al-Naḍr is among the most reliable scholars of Baghdad’ (3).

Aḥmad also said: ‘Abū al-Naḍr is more authoritative than Shadhān’ (4).

Aḥmad ibn Manṣūr al-Ramādī narrated: ‘One night I sat with Ibn Wārah and we discussed the companions of Shuʿbah. I said, “Abū al-Naḍr is more precise than Wahb ibn Jarīr.” He replied, “Wahb is more precise.” The next morning we went to Aḥmad ibn Ḥanbal, and he said, “Abū al-Naḍr wrote—”’