In his illuminations for Dante’s Paradiso, Giovanni di Paolo, one of the foremost painters of fifteenth-century Siena, reimagines contemporary religious iconographies, sometimes in highly unusual ways. This essay proposes that Giovanni’s images of the sacred in his illuminations for Paradiso invite forms of devotional engagement on the part of the reader-viewer. I suggest that Giovanni’s depictions of the sacred are a means of doing theology: that is, they explore the nature and activity of God and invite the viewer’s first-person engagement with the divine. In this view, Giovanni’s illuminations do not merely illustrate the narrative or epistemological content of the Commedia, but also share in the salvific mission that Dante claims for his poem. Studying Giovanni’s illuminations prompts us to reconsider the types of activity that reading the Commedia could involve.