In Augustine's vision, the conflict between the city of god and the city of man generates all kinds of creativity; the class predestined to join heaven goes to war with the class predestined to suffer eternal punishment; the clash between those two cities is the generator of “culture, distinction, vernacular, custom, rights, speech.”
As Augustine sees it, we inhabit one of those two cities: either the one made by love, one for god, or the one for self, one for flesh; one for spirit or one for the body. It's really a wonderful metaphor, extremely suggestive—a wonderful schema for organizing experience.1