Acts 12:5-7 (KJV)
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.
7 And, behold, the angel of the Lord came upon him, and a light shined in the prison: and he smote Peter on the side, and raised him up, saying, Arise up quickly. And his chains fell off from his hands.