Suddenly an angel of the Lord appeared and a light shone in the cell. He tapped Peter on the side and woke him, saying, "Get up quickly." And the chains fell off his wrists.
The angel said to him, "Fasten your belt and put on your sandals." He did so. Then he said to him, "Wrap your cloak around you and follow me."
Peter went out and followed him; he did not realize that what was happening with the angel's help was real; he thought he was seeing a vision.
After they had passed the first and the second guard, they came before the iron gate leading into the city. It opened for them of its own accord, and they went outside and walked along a lane, when suddenly the angel left him.
Then Peter came to himself and said, "Now I am sure that the Lord has sent his angel and rescued me from the hands of Herod and from all that the Jewish people were expecting."
As soon as he realized this, he went to the house of Mary, the mother of John whose other name was Mark, where many had gathered and were praying.
When he knocked at the outer gate, a maid named Rhoda came to answer.
On recognizing Peter's voice, she was so overjoyed that, instead of opening the gate, she ran in and announced that Peter was standing at the gate.
They said to her, "You are out of your mind!" But she insisted that it was so. They said, "It is his angel."
Meanwhile Peter continued knocking; and when they opened the gate, they saw him and were amazed.
He motioned to them with his hand to be silent, and described for them how the Lord had brought him out of the prison. And he added, "Tell this to James and to the believers." Then he left and went to another place.
References for Acts 12:17