Moore suggests that the catacombs and the cathedrals remind us of two very important truths—“God's sovereignty in sending down the faith, and the frailty of humanity as stewards of that faith.” Those dual truths of God’s power and our frailty has been the history of the church from the very beginning, and that continues to be story of the church today. Moore writes--
We can't romanticize the early persecuted church. After all, the New Testament Scriptures are often rebuking those churches for precisely the things we see going on in our churches today: division, carnality, immorality, arrogance (1 Cor. 4:7-13, 5:1-8, 6:1-8). And, if Christianity had remained in the catacombs, it is quite possible that you and I would have never encountered Christ.
The basilica at Saint John Lateran was planted there by the Emperor Constantine. His vision of a Christian empire was, of course, a failed experiment that led to persecution and all sorts of nominal Christianity. And yet, God used Constantine to end a bloody persecution and to, among other things, call together the church to deal with a deadly heresy or two. In the providence of God, the Trinitarian theism by which I critique the idea of Christian empire came down to me due, in part, to the unwitting actions of the prototypical Christian emperor.Moore warns us that if we see only the catacombs, then we might glamorize smallness in and of itself and thus make impotence equivalent to faith and holiness. If we do that, then we may excuse our inability to make any impact in the world around us. But if we only see the cathedrals, then we might tend to identify godliness with size, success, influence and power. We need to see God at work in both the catacombs and the cathedral… and we also need to see the fragility of human weakness at work in both. Moore ends his article with this reminder—
The kingdom of God is vast and tiny, universal and exclusive. Our story is that of a little flock and of an army awesome with banners. It's a Christianity of persecution and proliferation, of catacombs and cathedrals.