12 Would you learn the same truth respecting cities? What could be more illustrious than the cities of Sodom? For the houses and the buildings were splendid, and so were their walls; and the country was fat and fertile, and “like the Paradise of God.” But the tent of Abraham was mean and small, and had no fortification. Yet when a foreign war took place, the strangers broke down and took the walled cities, and departed, carrying away their inhabitants captives. Abraham, however, the citizen of the desert, they could not resist when he attacked them!
And so it was likely to be. For he had true piety: a power much greater than numbers and the defence of walls. If you are a Christian, no earthly city is yours. Of our City “the Builder and Maker is God.” Though we may gain possession of the whole world, we are withal but strangers and sojourners in it all! We are enrolled in heaven: our citizenship is there! Let us not, after the manner of little children, despise things that are great, and admire those which are little! Not our city's greatness, but virtue of soul is our ornament and defence.
If you suppose dignity to belong to a city, think how many persons must partake in this dignity, who are whoremongers, effeminate, depraved and full of ten thousand evil things, and at last despise such honour! But that City above is not of this kind; for it is impossible that he can be a partaker of it, who has not exhibited every virtue.
Source: Homilies on the Statues (New Advent)