Cath. (823–28), author of commentaries on the entire Bible. Ishoʿ bar Nun was born in the village of Beth Gabbare on the Tigris, near Mosul, around 745. He studied with Abraham bar Dashandad and, possibly after a short period of teaching at Seleucia, became a monk at the Great Monastery on Mt. Izla (founded by Abraham of Kashkar), where he also taught. Ishoʿ bar Nun later moved to Baghdad and then to Mosul, where he lived in the Monastery of Elijah. The chronology of these successive stays is highly uncertain as the many different sources provide at times conflicting information. In 823, Ishoʿ bar Nun was elected cath. of the Ch. of E., as the successor of Timotheos I, with whom he is said to have had a difficult relationship. He died in 828. Ishoʿ bar Nun should in all likelihood be distinguished from his namesake and contemporary who was bp. of Ram Hormizd in Beth Huzaye and who enjoyed the support of Timotheos, in whose letters he is occasionally mentioned.

In his capacity as cath., Ishoʿ bar Nun issued a number of canons, mainly dealing with matrimonial and hereditary law, which were incorporated in the collection of Syriac law books (ed. Sachau, with an addition by Sauget). In addition, Ishoʿ bar Nun is known as the author of a short treatise on homographs, which is extant in mss. in Iraq, but remains unpublished. His ‘Consolation Homilies’ and letters are only known in fragments. Ishoʿ bar Nun’s major work, which is preserved in its entirety (ms. Cambridge, Add. 2017), is his collection of ‘Selected Questions’ (Šuʾʾāle mgabbayyā) on the OT and NT. Presenting his work in the form of questions and answers, Ishoʿ bar Nun conveys much of the traditional exegesis of the Ch. of E. and respectfully quotes Theodore of Mopsuestia. Yet, he often goes his own way, creating more room for spiritual and even allegorizing exegesis. He may have found the inspiration for this new approach in his monastic background and in his familiarity with the works of Evagrius of Pontus. Thus expanding the horizons of E.-Syr. biblical interpretation, he had a lasting impact on the later tradition, the more so since much of Ishoʿ bar Nun’s work was incorporated into the normative commentaries by Ishoʿdad of Merv. Unfortunately, only small parts of the ‘Selected Questions’ have been published so far.