Saʿadiah Gaon on the Source of the Commandments: Between the Rational-Revelational Theory and the Decalogue as the Sum of the Commandments

In his writings, Sáadiah Gaon classifies the commandments by two different methods: in his prayer book and in his commentary to Sefer Yeẓirah, he uses a pedagogical-metaphysical classification of the commandments as rooted in the Decalogue, while in other writings-in particular, in the Book of Beliefs and Opinions-he uses an epistemological-Mu'tazilite classification of the commandments as rational or revelational. This article argues that in the Book of Beliefs and Opinions, which was written after Sa'adiah's prayer book and his commentary on Sefer Yeẓirah, Sa'adiah strives to reconcile the two modes of classification. He does so through an original claim that the commandments should be divided into four parts. This quadripartite division of the commandments serves as an intermediate categorization that bridges the two former classifications-the rational-revelational and the classification based on the Decalogue.