Divine providence is a mysterious, yet wonderful business. As the hymn writer put it, God moves in a mysterious way, His wonders to perform. One of the great benefits of a close scrutiny of the history of the church is, in retrospect, to see God's hand at work.
In the midst of the tumult or the vicissitudes it is usually very hard to discern what is going on. Three hundred years later its possible to discern what the Lord was building.
The Decian persecution of 250AD is one example. Decius was the first emperor (as far as we can tell) who ordered that everyone (apart from the Jews) had to make a sacrifice to the gods. This meant that an empire-wide persecution of Christians at the edit of the emperor was rolled out. Christians either had to make a sacrifice, or secure a certificate of having made one.
Many were apparently martyred; others fled or went into hiding; many compromised and conformed. It was a very difficult and dangerous time. Could any good come of it? Would the Church emerge stronger as a result? It did, but in unexpected ways.
Subsequently the Church was confronted with the issue of whether it was a gathered society of (near) perfected saints or a school for repentant and repenting sinners. So many had compromised and done some sort of obeisance to the gods that it appeared the very continuity of the Church was at stake.
By obliging so many Christians to lapse, Decius's edict split the Church in a argument over its image of itself: was it a school for sinners or a narrower society of saints? The issue was debated keenly throughout the Christian world . . . . In North Africa, the treatment of the lapsed was joined with a further issue: if a Christian had been baptized by somebody outside the "true" Church, must be be baptized again before he could return to the fold? The two controversies were connected: a harsh decision on the lapsed put yet more Christians outside the Church, into schism and heresy. [Robin Lane Fox, Pagans and Christians (New York: Alfred A. Knopf Inc., 1987) p.549.]The Church determined decisively that it was the latter: the Church was a society of imperfect repentant and repenting sinners, not a gathering of perfected uber-over-achieving-Christians. It also decided that the sacraments had veracity and significance apart from the "merit" of the one administering them. The implications were biblically based and far reaching. For one, it put paid to the common practice of delaying baptism until near death, for fear of lapsing back into sin again and losing salvation. It also helped undermine hitherto bizarre attempts to "overachieve" in order to win certain salvation--despite one's earlier failings--the three most common of which were to have a prophetic vision of some kind, be a "virgin", and/or achieve martyrdom.
Who would have predicted that such an amazing reformation of the Church would have resulted from a disastrous persecution that appeared to threaten its very integrity and existence.