I started using a devotional last year called "For the Love of God" by D.A. Carson. It is a great devotional that combines a read-through-the-Bible-in-year-plan with a short devotional/ theological observation on one of the passages for the day. Last week one of the selected passages was Acts 12. This passage is the account of Peter's arrest and subsequent release from prison by an angel of the Lord. When Peter is released he goes to a house where believers are praying (no doubt for him and his release).
"When he realized this, he went to the house of Mary, the mother of John whose other name was Mark, where many were gathered together and were praying. And when he knocked at the door of the gateway, a servant girl named Rhoda came to answer. Recognizing Peter's voice, in her joy she did not open the gate but ran in and reported that Peter was standing at the gate. They said to her, “You are out of your mind.” But she kept insisting that it was so, and they kept saying, “It is his angel!”But Peter continued knocking, and when they opened, they saw him and were amazed.