Abū Naṣr al-Sijzī, ʿUbayd Allāh b. Saʿīd b. Ḥātim al-Wāʾilī (d. Muḥarram 444/May 1052), a traditionist and author of a book in which he criticised the Ashʿarīs. According to Ibn al-Qaysarānī (p. 164), his nisba, al-Wāʾilī, refers to a village called Wāʾil in the region of Sijistān; but according to Ibn Mākūlā (7/398) he is called al-Wāʾilī because of his association with the clan of Bakr b. Wāʾil, and hence it may be presumed that he was of Arab origin.

Abū Naṣr's father was a religious scholar, and followed the juridical teachings of the Ḥanafī school (ʿAbd al-Qādir al-Qur…