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. But Paul shouted in a loud voice, “Do not harm yourself, for we are all here.” The jailer called for lights, and rushing in, he fell down trembling before Paul and Silas. Then he brought them outside and said, “Sirs, what must I do to be saved?” They answered, “Believe on the Lord Jesus, and you will be saved, you and your household.” They spoke the word of the Lord to him and to all who were in his house. At the same hour of the night he took them and washed their wounds; then he and his entire family were baptized without delay.Acts 16:23-33 (NRSV)