12 When he realized this, he went to the home of Mary, the mother of John Mark, where many were gathered for prayer. 13 He knocked at the door in the gate, and a servant girl named Rhoda came to open it. 14 When she recognized Peter's voice, she was so overjoyed that, instead of opening the door, she ran back inside and told everyone, "Peter is standing at the door!" 15 "You're out of your mind!" they said. When she insisted, they decided, "It must be his angel." 16 Meanwhile, Peter continued knocking. When they finally opened the door and saw him, they were amazed.
Matthew Henry's Commentary on Acts 12:12-16
Commentary on Acts 12:12-19
(Read Acts 12:12-19)
God's providence leaves room for the use of our prudence, though he has undertaken to perform and perfect what he has begun. These Christians continued in prayer for Peter, for they were truly in earnest. Thus men ought always to pray, and not to faint. As long as we are kept waiting for a mercy, we must continue praying for it. But sometimes that which we most earnestly wish for, we are most backward to believe. The Christian law of self-denial and of suffering for Christ, has not done away the natural law of caring for our own safety by lawful means. In times of public danger, all believers have God for their hiding-place; which is so secret, that the world cannot find them. Also, the instruments of persecution are themselves exposed to danger; the wrath of God hangs over all that engage in this hateful work. And the range of persecutors often vents itself on all in its way.