King Herod started persecuting certain members of the Church. He beheaded James the brother of John, and when he saw that this pleased the Jews he decided to arrest Peter as well. This was during the days of Unleavened Bread, and he put Peter in prison, assigning four squads of four soldiers each to guard him in turns. Herod meant to try Peter in public after the end of Passover week. All the time Peter was under guard the Church prayed to God for him unremittingly.

On the night before Herod was to try him, Peter was sleeping between two soldiers, fastened with double chains, while guards kept watch at the main entrance to the prison. Then suddenly the angel of the Lord stood there, and the cell was filled with light. He tapped Peter on the side and woke him. ‘Get up!’ he said ‘Hurry!’ – and the chains fell from his hands. The angel then said, ‘Put on your belt and sandals.’ After he had done this, the angel next said, ‘Wrap your cloak round you and follow me.’ Peter followed him, but had no idea that what the angel did was all happening in reality; he thought he was seeing a vision. They passed through two guard posts one after the other, and reached the iron gate leading to the city. This opened of its own accord; they went through it and had walked the whole length of one street when suddenly the angel left him. It was only then that Peter came to himself. ‘Now I know it is all true’ he said. ‘The Lord really did send his angel and has saved me from Herod and from all that the Jewish people were so certain would happen to me.’

From all my terrors the Lord set me free.

I will bless the Lord at all times,
  his praise always on my lips;
in the Lord my soul shall make its boast.
  The humble shall hear and be glad.

From all my terrors the Lord set me free.

Glorify the Lord with me.
  Together let us praise his name.
I sought the Lord and he answered me;
  from all my terrors he set me free.

From all my terrors the Lord set me free.

Look towards him and be radiant;
  let your faces not be abashed.
This poor man called, the Lord heard him
  and rescued him from all his distress.

From all my terrors the Lord set me free.

The angel of the Lord is encamped
  around those who revere him, to rescue them.
Taste and see that the Lord is good.
  He is happy who seeks refuge in him.

From all my terrors the Lord set me free him.

My life is already being poured away as a libation, and the time has come for me to be gone. I have fought the good fight to the end; I have run the race to the finish; I have kept the faith; all there is to come now is the crown of righteousness reserved for me, which the Lord, the righteous judge, will give to me on that Day; and not only to me but to all those who have longed for his Appearing.

The Lord stood by me and gave me power, so that through me the whole message might be proclaimed for all the pagans to hear; and so I was rescued from the lion’s mouth. The Lord will rescue me from all evil attempts on me, and bring me safely to his heavenly kingdom. To him be glory for ever and ever. Amen.

Alleluia, alleluia!
You are Peter, and on this rock I will build my church.
And the gates of the underworld can never hold out against it.
Alleluia!