But about midnight Paul and Silas were praying and singing hymns of praise to God, and the prisoners were listening to them; and suddenly there came a great earthquake, so that the foundations of the prison house were shaken; and immediately all the doors were opened and everyone's chains were unfastened.
Acts 16:25-26

Paul and Silas were in stocks (v.24) in a prison cell for no other reason than that through them God delivered a demon-possessed girl from her demonic tormentors. What would you or I be thinking and feeling if we were in that situation? Would singing praise songs be on the front burner of our minds? It was for them. Why?

Because they trusted God. Not just with a hope of Heaven when they died, but for everything, including life here and now!
Because they were people who were given to worship and praise the Lord—and not just when they were in the midst of favorable circumstances or in church.
Because they had, no doubt, already prayed to God as Paul later instructed the Philippians to do when troubled (Philippians 4:6-8). As a result, they were experiencing the peace of God that defies human understanding!
Because they, no doubt, encouraged each other in the moment.

Here is the deal: The time to prepare one’s heart and life to praise God when in the midst of persecution is not after persecution has already begun. The time to train oneself is before the fact.

Meditate on how God is worthy to be trusted.
Make worship and praise a way of life, not merely a religious activity.
Develop a prayer life so that when troubles come, you automatically go to prayer.
Practice being an encourager, so that when the chips are really down, you can lift others up!