As I’ve been preaching through 1 John, I’ve been constantly reminded of St. Augustine’s City of God and his insights into the two Cities, the City of Man and the City of God. He wrote this great treatise in 413 AD, after the Vandels had sacked Rome, which was called “the eternal city”. This conquest prompted Christians to understandable cry, “What’s happened to the City of God?” Augustine set out to alleviate the concern that Christ’s Kingdom (i.e., God’s City) had, in fact, fallen.
…the two cities were created by two kinds of love: the earthly city was created by self-love reaching the point of contempt for God, the Heavenly City by the love of God carried as far as contempt of self. In fact the earthly city glories in itself, the Heavenly City glories in the Lord. The former looks for glory from men, the latter finds its highest glory in God, the witness of a good conscience. The earthly lifts up its head in its own glory, the Heavenly City says to its God: ‘My glory; you life up my head.’ In the former, the lust for domination lords it over its princes as over the nations it subjugates; in the other both those put in authority and those subject to them serve one another in love, the rulers by their counsel, the subjects by obedience. The one city loves its own strength shown in its powerful leaders; the other says to its God, ‘I will love you, my Lord, my strength.’ [Augustine, City of God, 14.28]
Augustine drew these aforementioned conclusions from the Bible’s witness to these Cities. Spiritually-speaking, every man, woman, and child could be categorized as belonging to one of them. Either one was a citizen of the City of God or of the City of Man. These two cities were distinct in his mind, because each was defined in its relation to heaven or hell, God or the Devil. Just as a person cannot be both “born again” and “not born again,” you cannot be a citizen of both at the same time.
At its foundation, these two cities are characterized by two different loves. The City of Man was created by man’s self-love and its citizens are driven by self-love, while members of the City of God are created by God’s love and express their own love for God. Surely, this love isn’t perfected in this life, but it exists nevertheless. Christ doesn’t just save from the condemnation of hell, He also begins to save from the pollution of sin.