What could equal these souls? These men had been scourged, had received many, stripes, they had been misused, were in peril of their lives, were thrust into the inner prison, and set fast in the stocks: and for all this they did not suffer themselves to sleep, but kept vigil all the night. Do you mark what a blessing tribulation is? ...That the earthquake should not seem to have come of itself, there was this concurrent circumstance, bearing witness to it: "the doors were opened, and all their bonds were loosed." And it appears in the night-time; for the Apostles did not work for display, but for men's salvation...Here, they did but show the doors standing open, and it opened the doors of his heart, it loosed two sorts of chains; that (prisoner) kindled the (true) light; for the light in his heart was shining. "And he sprang in, and fell before them;" and he does not ask, How is this? What is this? but straightway he says, "What must I do to be saved?" What then answers Paul? "Believe on the Lord Jesus Christ, and thou shalt be saved, thou and thine house." (v. 31.) For this above all, wins men: that one's house also should be saved…
-St. John Chrysostom, Homily 36 on Acts 16, 4th Century