This article examines two medieval sermons that examine philosophic and halakhic issues: the Passover sermon of Hasdai Crescas, which discusses the laws of Passover, and a sermon of Zerahia Halevi Saladin, a disciple of Crescas, which probes an aspect of the laws of vows (nedarim). In the analysis of Zerahia’s sermon, a comparison is made between his discussion and Thomas Aquinas’s examination of vows in his Summa Theologica. The comparison establishes the dependency of Zerahia on Aquinas regarding this issue. Likewise, Zerahia’s sermon is compared with Crescas’s, and the relationship between the legal theories of Crescas and Zerahia is investigated. The articles concludes with a brief examination of the significance of the analysis these sermons for understanding of the impact of scholastic sources on Spanish-Jewish philosophy and the relationship between law and philosophy in the writings of Hasdai Crescas and his students.