Abū ‘Īsā al-Iṣfahānī, in the mid-eighth century, was the founder of one of the first Jewish sects to arise in Babylonia and Persia. As was the case for many other Jewish sects in the early gaonic period, it disappeared soon after its appearance, and even remnants of its writings have not survived. Thus our information about ‘Abū ‘Īsā and his doctrine comes from sometimes contradictory Karaite and Muslim sources.

According to the Muslim heresiographer al-Shahrastānī (d. 1153), Abū ‘Īsā was called Isaac ben Jacob, but others state that his name was Obed Elohim (Heb. wor…