Abū ʾl-Faḍl Sahl ibn Faḍl al-Tustarī (al-Dustarī; Heb. Jashar ben Ḥesed ben Jashar) was a Karaite scholar and exegete from the famous Tustarī family. He came from Tustar (Shustar) in Persia and toward the end of the eleventh century settled in Jerusalem, where he soon entered into conflict with Jeshua ben Judah, the head of the Karaite community there. Sahl was one of the last known Karaite scholars active in Jerusalem. His son was taken captive by the Crusaders in 1099. Composing all of his works in Arabic, he wrote numerous commentaries, but nothing has been preserved except fragme…