When the owners of the slave girl realized that their hope of making money was gone, they seized Paul and Silas and dragged them into the marketplace to face the authorities. After they had been severely flogged, they were thrown into prison, and the jailer was commanded to guard them carefully. Upon receiving such orders, he put them in the inner cell and fastened their feet in the stocks. About midnight Paul and Silas were praying and singing hymns to God, and the other prisoners were listening to them. Suddenly there was such a violent earthquake that the foundations of the prison were shaken. At once all the prison doors flew open, and everyone's chains came loose. The jailer woke up, and when he saw the prison doors open, he drew his sword and was about to kill himself because he thought the prisoners had escaped. But Paul shouted, "Don't harm yourself! We are all here!" The jailer called for lights, rushed in and fell trembling before Paul and Silas. He then brought them out and asked, "Sirs, what must I do to be saved?" - Acts 16: 19, 23-30 (NIV)