Exegesis
Yefet claims full freedom for the exegete, refusing to admit any authority for the interpretation of the Law; and, although he sometimes uses the thirteen hermeneutic rules laid down in the Mishnah, he denies their authority: they are to be applied, he claims, only when it is not possible to explain the passage literally. Thus, notwithstanding his veneration for Anan ben David, the founder of Karaism, and for Benjamin Nahawandi, he often rejects their interpretations.
Yefet was an adversary of the philosophico-allegorical treatment of Scripture. He, however, symbolizes several Biblical narrations, as, for instance, that of the burning bush, in which he finds a representation of Israel, whom enemies can not annihilate; and he admits that the Song of Solomon is an allegory.
Yefet attacked Islam with the greatest violence. For him the words of Isaiah, "Woe to thee that spoilest" (Isa. xxxiii. 1), refer to Mohammed, who robbed all nations and dealt treacherously with his own people, and Isa. xlvii. 9 to the downfall of Islam. In the following verse he sees an allusion to the sufferings inflicted by Muslim rulers on the Jews, who are loaded with heavy taxes, compelled to wear badges, forbidden to ride on horse-back, etc.
Yefet was no less bitter in his attacks on Christianity and on rabbinical Judaism, to which he refers many prophecies. Unlike his predecessors, he was not an opponent of secular science. To him the word "da'at" (Prov. i. 7) denotes "the knowledge" of astronomy, medicine, mathematics, etc., the study of which is to be undertaken before that of theology.
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