Acts 12:7

And behold an angel of the Lord stood by him, and a light shined in the cell: and he smote Peter on the side, and awoke him, saying, Rise up quickly. And his chains fell off from his hands.

Several things entered into Peter's deliverance. (1) There was a prayer meeting, mentioned later in Luke's narrative here, but already going on, and for days previously. (2) There was a messenger, in this case an angel of the Lord; but always there is a messenger when people are to be saved. "How shall they hear without a preacher?" (Romans 10:14). (3) There was light in that prison. The angel delivered the word of God to Peter; but the word of God is always light (Psalms 119:105); and like the "light" delivered to every sinner by faithful preachers of the word of God, it consisted of a command to arise and act. "Why tarriest thou? Arise and be baptized and wash away thy sins" (Acts 22:16). (4) Here the angel commanded Peter to get up and put on his sandals, and follow.

He smote Peter on the side ... Older readers of these lines will recall the manner of Pullman porters on passenger trains who always awakened their charges in exactly the same manner as here, striking them gently on the side, through the curtains, there never having been devised a better way of doing it without startling or frightening the sleeper. Thus, in an infinitesimal detail such as this, one sees the glorious truth of the word of God.