of his exceptional piety and continual study of the Law, Shimon was considered as one of those whose merit preserves the world, and therefore during his life the rainbow was never seen, that promise of God's forbearance not being needed. Teachings The fullest account of Shimon's teachings is to be found in W. Bacher's Agada der Tannaiten. When the Talmud attributes a teaching to Shimon without specifying which Shimon is meant, it means Shimon bar Yochai. Halacha Shimon's halakhot are very numerous; they appear in every tractate of the Talmud except Berakhot, Hallah, Ta'anit, Nedarim, Tamid, and Middot. He greatly valued the teaching of his master Akiva, and he is reported to have recommended his pupils to follow his own system of interpretation ("middot") because it was derived from that of Akiva. But this itself shows that Shimon did not follow his teacher in every point; indeed, as is shown below, he often differed from Akiva, declaring his own interpretations to be the better. He was independent in his halakhic decisions, and did not refrain from criticizing the tannaim of the preceding generations. He and Jose ben Halafta were generally of the same opinion; but sometimes Shimon sided with Meir. Like the other pupils of Akiva, who, wishing to perpetuate the latter's teaching, systematized it in the foundation of the Mishnah (Meir), Tosefta (Nehemiah), and Sifra (Judah), Shimon is credited with the authorship of the Sifre (a halakhic midrash to Numbers and Deuteronomy) and of the Mekhilta de-Rabbi Shimon (a similar midrash to Exodus). The particular characteristic of Shimon's teaching was that whether in a halakhah or in a aggadic interpretation of a Biblical command, he endeavored to find the underlying reason for it. This often resulted in a material modification of the command in question. From many instances the following may be taken: In the prohibition against taking a widow's garment in pledge, it was Judah ben Ilai's opinion that no difference is to be made between a rich and a poor widow. But Shimon gives the reason for such a prohibition, which was that if such a pledge were taken it would be necessary to return it every evening, and going to the widow's home every morning and evening might compromise her reputation. Consequently, he declares, the prohibition applies only in the case of a poor widow, since one who is rich would not need to have the