KJV:
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.
NASB:
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.