Biblical Commentaries
Joseph was on very friendly terms with his teacher Jacob Tam, with whom he carried on a learned correspondence (Sefer ha-Yashar, p. 71a). Besides tosafot on the greater part of the Talmud, he wrote a Biblical commentary marked by considerable acumen. Even more than Rashi, to whose exegetical school he belonged, he confined himself to literal interpretations (peshat). Anticipating later Biblical criticism, he assumed the presence of duplicate narratives in the Bible, and he strove to give rational explanations to the miraculous stories. Thus he interprets "tree of life" (Genesis ii. 9) as "tree of healing", explaining that the fruit of the tree possessed the virtue of healing the sick, without, however, bestowing eternal life. In regard to the transformation of Lot's wife into a pillar of salt (Gen. xix. 26) he explains that, disbelieving in the destruction of Sodom and Gomorrah, she lingered on the road, and was overtaken by the rain of brimstone and fire, which are usually mixed with salt.
Well acquainted with the Vulgate and Christian Biblical exegesis, Joseph, in commenting on Psalm ii., cites Jerome, whose explanation of the word he criticizes. His commentary on the Pentateuch is still extant in manuscript in the libraries of Leyden and Munich. Part of it, on Genesis and Exodus, was published by Jellinek (Leipsic, 1855). Extracts from the remaining books were published by Berliner in Peleṭat Soferim (1872).
His commentary on the Pentateuch has been published in Hebrew by Mossad HaRav Kook.
Read more about this topic: Joseph Ben Isaac Bekhor Shor