Final answer:
Augustine's concept of the two cities in 'The City of God' is ruled by the love of God in the heavenly city and the love of worldly desires in the earthly city.
Step-by-step explanation:
Augustine's two cities are ruled by two different loves. The "heavenly city" has a love of God, while the "earthly city" has a love of worldly desires. This dichotomy in the The City of God posits that the citizens of the heavenly city are driven by the love of God and the pursuit of spiritual peace. In contrast, those of the earthly city pursue earthly pleasures and possessions. Augustine's argument aims to elevate the spiritual pursuit over the material and to assure Christians that the spiritual kingdom is eternal, even if earthly kingdoms like the Roman Empire may fall.