A friend writes:
I'm about to embark on City of God for the first time . . . Is there any advice you have for me at this point? Anything I should look for or keep in mind as I'm reading it?
1. Keep in mind that this is definitely the longest work Augustine ever produced, and perhaps the longest work uniting a single, sustained argument in ancient history. In support of this argument, the author throws in about every tangential demonstration, record or fact that he can get his hands on. Thus, the reader is forced to work his way through volumes of seemingly irrelevant material - the minutiae of ancient Roman history and society, the natures and habits of various flora and fauna, the intricacies of Hebrew and Greek linguistic origins, etc. - in order to follow the thrust of the argument. Either buy a well-abridged version or learn to 'fast-forward' when the doctor of grace starts to wax ecstatic about the incandescent characteristics of peacock feathers, which he has somehow identified as the linchpin in his watertight argument against the Origenistic denial of a permanent hell.
2. It is customary to begin with book eleven in order to avoid all of the above, since books 1-10 involve an in-depth refutation of the classical Roman's view of his own history, point by historical point, generally focused on the foibles and moral failings of Roman aristocracy. But if this is your thing, by all means enjoy it. Note that St. Augustine's 'just war theory,' at least in its most seminal form, is contained in book 19. Remember that it's not going to look like the theory you learned in college; this theory has undergone quite a bit of development (most of it good).
3. Don't neglect the main themes. If this work is understood essentially as a consolation to teary-eyed Christians or a snipe at sneering pagans, it is profoundly misunderstood. Scholars now realize that Augustine had begun conceiving of this project, and had already worked through the main ideas behind it, at least ten years before the sack of Rome. It is not a hastily-written response to concurrent sociopolitical occurrences, but a systematic account of the world and its destiny which unites and synthesizes the entire theological career of one of the greatest minds in Christendom. It traces two classes of angels and men, those who love God and those who love only themselves, from their prehistorical origins, through biblical and secular history and beyond. It outlines the locus of the Church within the temporal world, while at the same time placing the temporal world in its own eschatological context. The final chapters, of course, are the best.
4. Enjoy. While not as personal or intimate as his Confessions, the City of God reveals the same passion and longing for God that mark all of Augustine's works. But it is here that he provides the systematic philosophical and theological foundations for that passion and longing.