In book 17, Augustine continues to trace the City of God through the people and story of the Old Testament. A big piece of his work in this book deals with biblical prophecy and how it relates to the future revelation of God in Jesus Christ. He argues that there are three kinds of Old Testament prophecies – prophecies related to the earthly Jerusalem, prophecies related to the heavenly Jerusalem, and prophecies related to both. Augustine wants to work primarily with prophecies that relate to the heavenly Jerusalem or to both the earthly and heavenly Jerusalem, since his goal is to describe the City of God. Regarding interpretation of these prophecies, he says that it is important to see when and how the historical meaning of a prophecy is wrapped in a spiritual meaning – he wants to say that not every episode has spiritual meaning just because we want it to, especially when there are important historical meanings.
My favorite of his readings in this section of the book 17 is his discussion of Hannah’s song from 1 Samuel. Augustine points toward Hannah as symbolizing the church and her song as a very clear prophecy of Christ. He invites the church to speak Hannah’s song with her, he shows how her ideas are completed in the coming of Christ, and he argues for seeing her words fulfilled in the remaking of the nation of Israel to include the Gentiles.
I also want to make note here of various references Augustine makes to Revelation – the City of God as a New or heavenly Jerusalem, its enemy Babylon, noting references to the number seven, the fulfillment of the Temple in the people of God, and an explanation of the church as Christ’s queen in the new creation. There is enough here to suggest that Revelation is one of Augustine’s sources for the concept of the City of God, even though he has not made an argument for that reading – it just seems to be presumed.