Peter Lombard's influential commentary on the Pauline Epistles, the Collectanea in omnes divi Pauli epistolas, has received little extended analysis in scholarly literature, despite its recognized importance both in its own right and as key for the development of his Sentences. This article presents a new approach to studying the Collectanea by analyzing how Lombard's commentary builds on the Glossa “Ordinaria” on the Pauline Epistles. The article argues for treating the Collectanea as a “historical act,” focusing on how Lombard engages with the biblical text and with authoritative sources within which he encounters the same biblical text embedded. The article further argues for the necessity of turning to the manuscripts of both the Collectanea and the Glossa, rather than continuing to rely on inadequate early modern printed editions or the Patrologia Latina. The article then uses Lombard's discussion of faith at Romans 1:17 as a case study, demonstrating the way in which Lombard begins from the Glossa, clarifies its ambiguities, and moves his analysis forward through his use of other auctoritates and theological quaestiones. A comparison with Lombard's treatment of faith in the Sentences highlights the close links between Lombard's biblical lectures and this later work. The article concludes by arguing that scholastic biblical exegesis and theology should be treated as primarily a classroom activity, with the glossed Bible as the central focus. Discussion of Lombard's work should draw on much recent scholarship that has begun to uncover the layers of orality within the textual history of scholastic works.