Mekhilta of Rabbi Shimon bar Yochai
The Mekhilta of Rabbi Shimon bar Yochai (, "Mekhilta de-Rabbi Shimon bar Yoḥai") is a Halakic midrash on Exodus from the school of Rabbi Akiva, attributed to Shimon bar Yochai. No midrash of this name is mentioned in Talmudic literature, but medieval authors refer to one which they call either "Mekhilta de-R. Simeon b. Yohai" or "Mekhilta Ahrita de-R. Shimon", or simply "Mekhilta Akheret" ("another mekhilta"). References by later writers. Passages from this Mekhilta are cited in later works, especially by Nahmanides in his Pentateuchal commentary, and by R. Todros ha-Levi  in his works "Sefer ha-Razim" and "Otzar ha-Kabod". Until the early 1900s, aside from these quotations and some given by certain authors of the 16th century (such as Elijah Mizrahi in his "Sefer ha-Mizrachi", R. Shem-Ṭob b. Abraham in his "Migdal Oz", and R. Meir ibn Gabbai in his "Tola'at Ya'akov"), the only known extract of any length from "Mekhilta de-R. Shimon" was the one published by R. Isaac Elijah Landau from a manuscript of R. Abraham Halami, as an appendix to his edition of the Mekhilta. There were, therefore, various erroneous opinions regarding this  lost work. Zunz considered it as a kabbalistic work ascribed to R. Shimon bar Yochai. M. H. Landauer identified it with the "Mekhilta of Rabbi Ishmael", while J. Perles held that the medieval authors applied the name "Mekhilta de-R. Shimon" merely to his maxims which were included in the "Mekhilta de-R. Yishmael", since separate sentences could be called "mekhilta". M. Friedmann was the first to maintain that, in addition to R. Ishmael's work, there was a halakhic midrash to Exodus by R. Shimon, which was called the "Mekhilta de-R. Shimon," and that this Mekhilta formed part  of the Sifre mentioned in the Talmud Bavli. This assumption of Friedmann's was subsequently confirmed by the publication of a geonic responsum, where a baraita from the "Sifre de-Bei Rav" to Exodus is quoted, which is the same passage as that cited by Nahmanides from the "Mekhilta de-R. Shimon b. Yochai", in his commentary on Exodus 22:12. This extract designates the work of R. Ishmael as the "Mekhilta of Palestine," in contradistinction to R. Shimon b. Yochai's midrash. It is clear, therefore, that the Mekhilta of R. Shimon was implied in the title Sifre de-Bei  Rav; and it is mentioned in the Midrash Tehillim under the Hebrew name "Middot R. Shimon b. Yohai." It is possible also that Shimon himself intended to refer to his midrash in his saying: "My sons, learn my "middot"; for my "middot" are those extracted and taught by Rabbi Akiva". The Judean sources, the Yerushalmi and the aggadic midrashim, introduce baraitot from this Mekhilta with the phrase, "Teni R. Shimon" = "R. Shimon has taught". The phrase "Tana de-Bei R. Shimon" is extremely rare, however, in the Talmud Bavli, where this midrash ranks as one of the "Sifre de -Bei Rav". Many sentences of R. Shimon are quoted there in the name of his son Eleazar, so that Hoffmann has very plausibly concluded that Eleazar edited his father's midrash. Current status. The Mekhilta de-R. Shim'on had disappeared, but some extracts from it were preserved in the collection known as "Midrash haGadol", as Israel Lewy first pointed out. These fragments were collected by David Zvi Hoffmann and published under the title "Mechilta des R. Simon b. Jochai". This Mekhilta compiled from Midrash haGadol preserves abundant material from the earliest Scriptural commentaries, quoting, for instance, a sentence from the  Doreshei Reshumot on Exodus 21:12 which is found nowhere else. It contains also much from post-Talmudic literature, for the collector and redactor of the Midrash haGadol had a peculiar way of dressing sentences of such medieval authorities as Rashi, Ibn Ezra, "Arukh", and Maimonides in midrashic garb and presenting them as ancient maxims. A critical version, using newly discovered fragments of texts, was later published by Yaakov Nahum Epstein and his student Ezra Zion Melamed. The publication is an attempt to reconstruct the original Mekhilta of Rabbi Shimon bar Yochai, based on all extant sources. Mekhilta of Rabbi Shimon