“And suddenly there was a great earthquake, so that the foundations of the prison were shaken: and immediately all the doors were opened, and every one's bands were loosed.”
King James Version (KJV)
16:24 Secured their feet in the stocks - These were probably those large pieces of wood, in use among the Romans, which not only loaded the legs of the prisoner, but also kept them extended in a very painful manner.
16:25 Paul and Silas sung a hymn to God - Notwithstanding weariness, hunger stripes, and blood. And the prisoners heard - A song to which they were not accustomed.
16:28 But Paul cried - As they were all then in the dark, it is not easy to say, how Paul knew of the jailer's purpose; unless it were by some immediate notice from God, which is by no means incredible. With a loud voice - Through earnestness, and because he was at some distance. Do thyself no harm - Although the Christian faith opens the prospect into another life, yet it absolutely forbids and effectually prevents a man's discharging himself from this.
Ac 16:26 There was a great earthquake. God heard them, too. See Ac 4:31. It was God's angel to loose their bonds, open the prison doors, and magnify their work.