What is the difference between the two cities?

The City of Man represents the non-believers specifically the Romans. After the fall of the Roman Empire, Romans accused Christians of being the main reason for their fall. However, Augustine condemns the Romans for such accusations and insists that worshipping their pagan gods was the only reason they were destroyed. They lacked faith in the one true God and hence allowed immorality to reign in their kingdom. People were corrupt and greedy hence there was no order. The author also poses the question of why the pagan gods never came to help their believers in their time of need.

The City of God represents the Christians. In this section, Augustine praises the believers for their faith and contribution to humanity. According to Augustine most of the problems in the world are spiritual, not physical and Christianity has played a major role in solving these problems. Augustine also laments at the suffering Christians have gone through for decades in the hands of pagans. Nevertheless, he praises their determination and loyalty to God, who unlike the pagan gods, shows up in their time of need.