Acts 12:4-6

And when he had seized him, he put him in prison, delivering him over to four squads of soldiers to guard him, intending after the Passover to bring him out to the people. So Peter was kept in prison, but earnest prayer for him was made to God by the church. Now when Herod was about to bring him out, on that very night, Peter was sleeping between two soldiers, bound with two chains, and sentries before the door were guarding the prison.