Acts 12:6; Acts 12:7

6 On the very night when Herod was about to bring him forward, Peter was sleeping between two soldiers, bound with two chains, and guards in front of the door were watching over the prison.

7 And behold, an angel of the Lord suddenly appeared and a light shone in the cell; and he struck Peter's side and woke him up, saying, "Get up quickly." And his chains fell off his hands.