Acts 12: It's His Angel!
I was listening to Acts last night, and noticed a little detail that sparked my curiosity. In Acts 12, James has just been killed and Peter has been imprisoned, a group of followers are praying for his release --- but given the recent execution of James, it’s likely they expected the worse. However, little known to them Peter has just been miraculously freed from prison:
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.
What peaked my interest was that, instead of thinking Peter was knocking (who surely was not released so quickly) they comment first that the girl is crazy, then that it must be Peter’s “angel.” That reminded me of the “Sunday School” understanding that when you die you will go to Heaven and become an angel; this of course isn’t attested to in the Scriptures.
However, what to make of this verse then? Why would Peter’s angel have the same voice as Peter? According to I. Howard Marshall:
When the servant girl heard Peter’s voice in response to her query, she was so surprised and overjoyed she ran back into the house to tell her exciting news without opening the door. The people indoors refused to believe her story. First, they said she was out of her mind. When they could not shake her story, they thought it must be Peter’s angel. This curious reference must be to some sort of ‘heavenly’ counterpart to a person, having the same physical appearance.
The Jews believed people had guardian angles (see Matt 18:10 for an echo of this belief), and there is some evidence (admittedly much later then the New Testament and not all together easy to interpret) that guardian angels were thought to bare the image of the persons whom they protected. The suspicion of the people in the house was in this case false, since it really was Peter himself; Luke says nothing to indicate the supposition rested on a sound doctrine of angels and it is most likely that it is nothing more then a Jewish superstition which he sites but does not necessarily corroborate. 
This would seem to satisfy the reference to angel if the servant girl has seen Peter, but apparently she hadn’t seen him. Of course, the people inside might not have known that she only heard him and just assumed she had seen him, and that is why she was so sure. However, the time delay between servant girl’s outburst and opening of the door seems to have been at least a few minutes since Peter “kept on knocking.” So apparently this superstition about angels may have logically flowed to a belief that a person’s angel could look, and speak in the same fashion. This would make plenty of sense. God’s angles were his messengers, and spoke for him --- so in a way they were the ‘voice of God.’
 I. Howard Marshall, Acts The Tyndal New Testament Commentaries, First Edition (Eerdmans Publishing Co. 1980)