A quarter-century ago, David T. Runia noted a “lack of a solid foundation for the study of Philo’s influence on Origen.” In 2000, Annewies van den Hoek supplied just such a foundation by publishing a truly impressive catalogue of passages where Origen may be dependent on or inspired by Philo. Since that time appreciation for Origen’s estimation of Philo as an exegetical model has only deepened (e.g., Ramelli [2012]). This paper further explores Philo’s influence on Origen, not only on particular exegetical points or hermeneutical procedures, but at a more foundational level of hermeneutical principle: the concepts of prophets and prophecy. Significant scholarly attention has been given to the views of prophecy to be found both in Philo (e.g., Burkhardt [1988], Winston [1989], Levison [1995]) and in Origen (e.g., Nardoni [1984], Hauck [1989], Sfameni Gasparro [1995]), and while some preliminary attention has been given to comparing the two thinkers on the matter, much remains to be done. Focusing on the paradigmatic case of Moses, “the greatest and most perfect of men” (Philo, Mos. 1.1) and “the greatest of the prophets” (Origen, Hom. Ex. 3.1), I argue that Philo is an important influence on Origen’s understanding of prophecy. (While we know that Clement read Philo’s Vita Mosis [see Strom. 1.153], I will argue briefly against viewing Clement as an intermediary between Philo and Origen on this point.) Origen does not take over Philo’s view wholesale; the two Alexandrians diverge most notably on the complex question of the prophet’s condition during divine inspiration. Rather, Origen selects particular elements of Philo’s presentation of Moses, modifying, adapting, and synthesizing them into his own Christian view of prophecy as participation in the Logos. Specifically, Origen builds on Philo’s insistence on the interpretative value of the prophet’s bios — knowledge of “the man himself as he really was” (Mos. 1.1) — with its attendant emphasis on the indispensability of virtue and friendship with God for true prophecy. Origen will reconfigure this emphasis by making its core criterion the kenotic philanthropia of Christ, but, strikingly, seeds of this view are also discernible in Philo’s profile of Moses. Finally, I argue that the significance of Philo’s contribution is fully appreciated only when it is recognized that Origen’s concept of prophecy is centrally constitutive of his case for the unity of the two testaments of the Christian Bible.