My voice sticks in my throat; and, as I dictate, sobs choke my utterance. The City which had taken the whole world was itself taken.” 
The churchman Jerome wrote those words when he heard of the sack of Rome by Alaric I and his Visigoths in A.D. 410. Truth be told, Alaric’s sack of Rome caused far less damage and death than you might imagine, but the emotional and psychological effects reverberated throughout the Empire, as we see in Jerome’s reaction above. For centuries, Rome had been known as the Eternal City. Her armies had been invincible. She controlled and safeguarded the seas, and her culture shaped the known world. But in 410, as Susan Bauer says, Rome “was so diminished that a band of Visigoths could over run it with almost no effort.”  Rome was not the Eternal City. She had never been.
Thirteen years later Augustine, the Bishop of Hippo in North Africa, published City of God, a book that laid the foundation for the next thousand years of Christian thought and practice. As Rome’s decline progressed, many wondered why she had fallen. Some argued that God judged her for her decadence. Others believed Christianity itself was to blame for having supplanted the ancient cultic practices which had reigned during Rome’s rise to prominence. Augustine’s City of God made a potent argument, which Bauer summarizes for us:
“Rome, he wrote, was a city of man; and in all times, at all places, the cities of men exist side by side with the city of God, the true Eternal City, the unseen spiritual kingdom. Men choose which city they will occupy, and although the goals of the two cities may occasionally intersect (and their citizens may find themselves able to cooperate with each other), the ultimate purposes of their citizens diverge. The city of man seeks power; the citizens of God’s city seek only the worship and glory of God. Rome had fallen, but the city of God would endure forever.” 
Much can be applied from Augustine’s 5th-century reflection on Rome to our 21st-century congregation in America, more than the space of this letter will allow. But, let me draw out a few applications.
First, recognize that the Church is the city on a hill Christ spoke of, not Rome, not Calvin’s Geneva, not America. Christ himself tells us that in this age, the wheat of his church is intermixed in a field sown with weeds. (Matt. 13:24) We ought to love our nation because she is ours. These are the people into which the Sovereign God has sown us. But our nation is not ultimate. America, like Rome, is not the Eternal City, the Church is.
Second, the greatest migration of people today is not from one earthly nation into another, it’s a migration from the City of Man into the City of God.
Many who now call the city of destruction their home are future citizens of the Eternal City of God.
And, as the Church, our ultimate responsibility is to cry out against the City of Man and all her excess, decadence, and rebellion. The Church displays, in stark relief to the world, a counterculture of God’s Law and Grace. As the author of Hebrews put it, we have a city, “that has foundations, whose designer and builder is God.” (Heb. 11:10)
Finally, the City of God, the Church, is integral to our identity as persons. As national cohesion unravels in the West and expressive individualism runs rampant, our heavenly citizenship stabilizes and unifies our church. We are not individualist atoms. We are living stones, stacked one on top of the other into a house. We are a chosen race, a holy nation, a people for his own possession. (1 Pet. 2:5-9) Every Lord’s Day, we confess with one voice our belief in the communion of saints; that is, we are united in Christ with saints in every nation and every age. In Christ, God has united us with father Abraham, deliverer Moses, and kingly David, along with Augustine, Dietrich Bonhoeffer, and Billy Graham.
Augustine’s City of God prepared the church for faithfulness in a declining empire nearly 1,600 years ago. It may be time, once again, to take up and read his words.
Some of you will want to read Augustine for yourself. Every Christian ought to read his pioneering memoir, Confessions. It’s a short, yet potent, narrative of Augustine’s conversion to Christ. Those who desire to read City of God will want to find the abridged edition by Vernon Bourke. Publication details below:
Augustine, and Gerald G. Walsh. The City of God: An Abridged Version from the Translation by Gerald G. Walsh and Others with a Condensation of the Original Foreword by Etienne Gilson. Edited, with an Introd. Garden City, N.Y,: Image Books, 1958.
 Jerome, Letter CXXVII (To Principia)
 Susan Wise Bauer, The History of the Medieval World (New York; W. W. Norton & Company, 2010) 83.
 Bauer, 84.