To some of them this seemed so unbelievable that they were more ready to think Rhoda had lost her mind. Others said that Peter's angel had appeared. But Rhoda kept insisting on what she had said.
The perplexity was soon resolved, but it did exist. The writer of Acts found it necessary to include it in his sacred chronicle. By the vivid portrayal of how unbelievable Peter's release seemed to everyone, he showed the greatness of God's work.
He also showed the weakness of human understanding before what God does. God conquers the ordinances of nature and overthrows all the devices of human malice, even where ordinary human judgment sees no means for the opposite outcome.
All who saw the miracle were amazed, that is, they passed beyond the usual representations and concepts on which the mind bases its reasoning. Of the servant girl Rhoda they even said that she was out of her mind.
Yet she looked at the matter more soberly than all. Only one thing is unclear: why did she not open the doors for Peter? One may say that the judgment about her was partly correct, but at the same time almost incorrect.
She was so seized by joy and by the desire to share it that everything else receded into the background. This was all the more so because Peter clearly had full opportunity to wait a minute or two.
All interpreters find it natural that she could have done this from joy, and that according to the purposes of God's providence she even had to do so.
"Notice the reverence of the maiden," writes Blessed Theophylact. "For joy, it says, she did not open. But this turned out well. Otherwise the others, astonished by his unexpected appearance, might not have believed it was he, since even then they did not wish to believe."
But how did they then come to the thought that it was an angel? "They reasoned so because of the shortness of the time," says Saint John Chrysostom. Blessed Theophylact adds that they said this in accordance with their situation.
For it is said, "Where two or three are gathered in My name, there am I in the midst of them" (Mt 18:20). And where Christ is, there the archangels and the other powers must also be.
But here, evidently, Peter's guardian angel is meant (cf. Heb 1:14). Saint John Chrysostom remarks: "From this the truth is evident, that each of us has a guardian angel."
Perhaps this was a faint conjecture that Peter's guardian angel could have preserved him and brought him here, or at least announced something about him for the consolation or encouragement of the believers.
"The servant girl's joyful confusion at the voice of the Apostle Peter, so that she forgets to open the door of the house to him, but runs first to announce it to the hosts and guests; the good-natured, mocking question of the latter, 'Are you in your right mind?'; the common, noisy joy of all present at seeing the Apostle Peter: all this shows that the account was copied from reality."