Acts 12:1-6 (KJV)
Now about that time Herod the king stretched forth his hands to vex certain of the church.
2 And he killed James the brother of John with the sword.
3 And because he saw it pleased the Jews, he proceeded further to take Peter also. (Then were the days of unleavened bread.)
4 And when he had apprehended him, he put him in prison, and delivered him to four quaternions of soldiers to keep him; intending after Easter to bring him forth to the people.
5 Peter therefore was kept in prison: but prayer was made without ceasing of the church unto God for him.
6 And when Herod would have brought him forth, the same night Peter was sleeping between two soldiers, bound with two chains: and the keepers before the door kept the prison.