This chapter examines Pauline letters in the light of Seneca’s fictive Moral Epistles addressed to his pupil “Lucilius.” It indicates the various authorial strategies deployed in the development of basic letter elements, such as addressees, situational discourse, and addressor, that serve in the promotion of disciplinary teachings and compares those strategies among the two collections. The chapter argues that the letter genre is in many ways an ideal medium for the advancement of disciplinary teachings by an authoritative instructor. The benefits of adopting the letter genre for persuasive teachings include its friendly and trustworthy domain, its appeal to external readers naturally drawn to incidents seemingly meant for others, and that it easily permits and even anticipates the promotion of self. It likewise highlights the versatility of the genre, its historic use in philosophical teachings, and its easy accommodation to a wide range of subgenres, including biography, autobiography, dialog, and narrative. Similarity in the use of epistolary features across the two collections contributes to the book’s thesis that Pauline authors, like Seneca, exploited the genre for teachings to secondary readers.