Late antique laws are rhetorically crafted and often bolstered by expressions of popularized philosophy and theology. This article presents historical evidence that reveals a close link between literary culture and the drafting of laws. It then examines a constitution of Valentinian III against tomb violators (Nouella Valentiniani 23) as case-study. The rhetorical preamble of this law presents a concise argument for the immortality of the soul. At first sight, the phrase nec uana fides which features in this context seems nothing more than a learned, yet merely ornamental, allusion to Virgil (Aen. 4.12) with no further bearing on the content. This article argues that the passage of Nouella Valentiniani 23 might in fact be a reminiscence of Prudentius (Cath. 3.196), who had used the same Virgilian tag to allude to Paul (1 Cor. 15:13–17), thus expressing faith in the immortality of the soul and in the doctrine of resurrection. The author of the Virgilian cento uersus ad gratiam Domini (or Tityrus) also redeployed the same phrase nec uana fides with reference to the immortality of the soul, and the cento’s intertextual relationship with Prudentius might contribute to the evidence about its date. This complex net of intertextual references (Virgil, Paul, Prudentius) bestows authority on this legal admonition and justifies an appreciation of the late Roman constitutions as literature.