aint Augustine, like all good teachers likes to ramble, just a bit. It will be a dozen or more “books” into The City of God before Augustine gets to the real meat of his subject, but the journey to the start, as it were, is quite fascinating. Within the opening “books,” what we would call “chapters” today, one will find a host of subjects, ranging from theology to philosophy, with a good bit of Roman history mixed all through, and a good bit more besides. In the next to the last chapter of the first book of The City of God, Augustine lays out the purpose of the book. It is a gracious explanation of the mixed multitude that the visible church is made of; an explanation filled with hope, and the gospel.
But let this city bear in mind, that among her enemies lie hid those who are destined to be fellow-citizens, that she may not think it a fruitless labour to bear what they inflict as enemies until they become confessors of the faith. So, too, as long as she is a stranger in the world, the cit of God has in her communion, and bound to her by the sacraments, some who shall not eternally dwell in the lot of the saints. Of these, some are not now recognised; others declare themselves, and do not hesitate to make common cause with our enemies in murmuring against God, whose sacramental badge they wear. These men you may to-day see thronging the churches with us, to-morrow crowding the theatres with the godless. But we have the less reason to despair of the reclamation even of such persons, if among our most declared enemies there are now some, unknown to themselves, who are destined to become our friends. In truth, these two cities are entangled together in this world, and intermixed until the last judgment effect their separation. I now proceed to speak, as God shall help me, of the rise, progress, and end of these two cities; and what I write, I write for the glory of the city of God, that, being placed in comparison with the other, it may shine with a brighter lustre.
Saint Augustine, The City of God; book 1, chapter 35.