We studied Acts 16 in prayer meeting/Bible study time tonight at church. I was struck again by the capacity of Paul and Silas to engage in a time of prayer and praise after having been severely beaten with rods, thrown into the inner part of a prison, and having their feet placed in stocks. I suspect most of us would have been bemoaning our lot and complaining to God about our unjust suffering. They on the other hand deemed it a cause for rejoicing and singing praises.
The passage says that the other prisoners were all listening to them. I'd suggest that they too were awestruck by the unusual behavior of these fellow inmates. I think that's in large part the explanation for why they didn't flee and escape when the earthquake rattled open the doors and loosened their chains.
We observed as well the evidence of the power of the gospel to change a life in the immediate behavior of the Philippian jailer who took Paul and Silas to his home, washed their wounds, and offered them food. While such radical transformation isn't always instantly visible, a genuine conversion experience will inevitably produce a changed life.