And they said unto her, Thou art mad. But she constantly affirmed that it was even so. Then said they, It is his angel.
Note 12 at Ac 12:15: The disciples were praying for Peter, but when he was reported as being freed from prison, they didn't believe it. Either they were not praying for his release, or they had hardened hearts that caused them to be amazed when they saw the miraculous, such as the disciples had in Mr 6:51 (see note 10 at Mr 6:52).
Note 13 at Ac 12:15: They didn't say it was an angel but rather his angel. This reflects their belief that everyone has his or her own angel, assigned by the Lord. Jesus made reference to a child's angel beholding the Lord's face continually, ready to minister on that child's behalf (see note 3 at Mt 18:10).