IBN YASHUSH, ISAAC ABU IBRAHIM

IBN YASHUSH, ISAAC ABU IBRAHIM (also known by his Arab name, Abū Ibrāhīm ibn Kastār; d. 1056), Hebrew grammarian and Bible commentator. Born in Toledo, he was court physician of the ruler of Denia (a maritime power on the eastern coast of the Iberian peninsula) Mujāhid al-ʿAmirī and of his son Iqbāl al-Dawla. The author of the "history of Arabian physicians," Ibn Abī Uṣaybiʿa, praises Ibn Yashush as a person of sharp mind and gentle manners who was well versed in grammar, philosophy, Bible, and Jewish law. The best known of his works is his book on accidence (i.e., on the inflections of verbs) called in Hebrew Sefer ha-Ẓerufim, which some scholars identify with the manuscript Kitāb al-Taṣārīf extant in the Oxford and Leningrad libraries. Fragments of this work were published by Derenbourg (Opuscules et Traités d'About Walid Merwan ibn Djanah (1880), p. xx) and by Kokowzoff (Historii yevreyskoy filologii 2 (1916), 117ff., 131ff., 174, 176ff.). Ibn Yashush was regarded as one of the greatest Hebrew grammarians by medieval Hebrew scholars such as moses ibn ezra who, in his introduction to Moznayim, lists him among the sages of the holy tongue. Ibn Yashush wrote a Bible commentary named Yiẓḥaki in which the method of investigation comes very close to that of modern Bible criticism. He was sharply criticized for his bold approach and many scholars believe that Abraham ibn Ezra's sharp attack against the "blundering (or silly) fellow" (ליבהמה קחצי) who held that the chronology of the Edomite kings (Gen. 36:31ff.) was composed in the days of King jehoshaphat was aimed against Ibn Yashush whose "book ought to be burned" (Ibn Ezra's commentary to Gen., loc. cit.). -BIBLIOGRAPHY: Steinschneider, Arab Lit, 135–6, no. 89; Graetz, Gesch, 6 (18943), 42–43; Bacher, in: J. Winter and A. Wuensche (eds.), Juedische Literatur, 2 (1894), 262–3; Ashtor, Korot, 2 (19662), 184f., 386f. (Eliyahu Ashtor)