Palestinian amora of the third century. He engaged in various midrashic controversies. Among them was one with Levi concerning 1 Kings 7:50 (Cant. R. on 3:10), and another with Kahana concerning Joseph's abstention from wine after his imprisonment by his brothers (Shab. 139a; Gen. R. , ). With reference to the saying that the curse inflicted upon the world consists in the bringing forth of gnats, flies, and other insects, Yiẓḥaḳ states that even these creatures are of use in the world (Gen. R. 5:9).