Acts 12:4-5

4After the soldiers caught Peter, they put him in prison. While he was in prison, four different groups of soldiers guarded him. There were four soldiers in each group. Herod wanted to judge Peter in front of everybody. After the Passover festival had finished, he would bring Peter out of the prison to do this.

5So Herod kept Peter in prison. But during that time, the group of believers prayed that God would help Peter.