Acts 16:20-27 NRSV
When they had brought them before the magistrates, they said, “These men are disturbing our city; they are Jews and are advocating customs that are not lawful for us as Romans to adopt or observe.” The crowd joined in attacking them, and the magistrates had them stripped of their clothing and ordered them to be beaten with rods. After they had given them a severe flogging, they threw them into prison and ordered the jailer to keep them securely. Following these instructions, he put them in the innermost cell and fastened their feet in the stocks.
About midnight Paul and Silas were praying and singing hymns to God, and the prisoners were listening to them. Suddenly there was an earthquake, so violent that the foundations of the prison were shaken; and immediately all the doors were opened and everyone's chains were unfastened. When the jailer woke up and saw the prison doors wide open, he drew his sword and was about to kill himself, since he supposed that the prisoners had escaped.
NRSV: New Revised Standard Version