Halakhic Exegesis
Ishmael gradually developed a system of halakhic exegesis which, while running parallel with that of Rabbi Akiva, is admitted to be the more logical. Indeed, he established the principles of the logical method by which laws may be deduced from laws and important decisions founded on the plain phraseology of the Scriptures. Like Akiva, he opened up a wide field for halakhic induction, but, unlike Akiva, he required more than a mere jot or a letter as a basis for making important rulings (Sanhedrin, 51b).
Ishmael was of opinion that the Torah was conveyed in the language of man (Yerushalmi Yevamot, viii. 8d; Yerushalmi Nedarim, i. 36c), and that therefore a seemingly pleonastic word or syllable can not be taken as a basis for new deductions. In discussing a supposititious case with Akiva, he once exclaimed, "Wilt thou indeed decree death by fire on the strength of a single letter?" (Sanhedrin, 51b). The plain sense of the Scriptural text, irrespective of its verbal figures, was by him considered the only safe guide.
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