The Acts 12:4-6

whom having seized he put in prison, having delivered him to four quaternions of soldiers to keep, purposing after the passover to bring him out to the people. Peter therefore was kept in the prison; but unceasing prayer was made by the assembly to God concerning him. And when Herod was going to bring him forth, that night Peter was sleeping between two soldiers, bound with two chains, and guards before the door kept the prison.