(a) But let us look over again what has been said. “There was a certain man in Cæsarea,” etc. (Recapitulation, v. 1, 2.) Observe with whom the beginning of the Gentiles is made— with “a devout man,” and one proved to be worthy by his works. For if, though the case be so, they are still offended, if this had not been the case, what would not have been the consequence! But mark the greatness of the assurance. (c) To this end all is done (in the way it is done), and the affair takes its beginning from Judea. (d) “He saw in a vision, evidently,” etc..
It was not in his sleep that the Angel appeared to him, but while he was awake, in the daytime, “about the ninth hour. He saw an Angel of God coming in unto him, and saying unto him, Cornelius. And when he looked on him, he was afraid.” So occupied was he with himself. Implying, that it was in consequence of the Angel's calling him by a voice that he saw him; as, had he not called him, he would not have seen him: so taken up was he with the act in which he was engaged. But the Angel says to him, “Your prayers and your alms have come up for a memorial before God, and now send men to Joppa, and call for one Simon, who is called Peter.” So far, he signified that the sending for him would be for good consequences, but in what way good, he did not intimate. So, neither does Peter relate the whole matter, but everywhere, the narratives are in part only, for the purpose of making the hearers apply their minds to what is said.
“Send and call for Simon:” in like manner the Angel only calls Philip. “And as they went on their journey, and drew near to the city”: in order that Peter should not be in perplexity too long. “Peter went up upon the housetop,” etc. Observe, that not even his hunger forced him to have recourse to the sheet. “Rise, Peter,” says the Voice, “kill and eat.” Probably he was on his knees when he saw the vision.— To me it seems that this also denotes the Gospel (or, “the Preaching”).
That the thing taking place was of God (the circumstances made evident, namely), both that he sees it (descending) from above, and that he is in a trance; and, that the voice comes from thence, and the thrice confessing that the creatures there were unclean, and its coming from thence, and being drawn back there (all this), is a mighty token of the cleanness (imparted to them).— But why is this done? For the sake of those thereafter, to whom he is about to relate it. For to himself it had been said, “Go not into the way of the Gentiles.” * * For if Paul needed both (to give) circumcision, and (to offer) sacrifice, much more (was some assurance needed) then, in the beginning of the Preaching, while they were as yet weaker. — Observe too how he did not at once receive them.
For, it says, they “called, and asked, whether Simon, which was surnamed Peter, were lodging there.” As it was a mean looking house, they asked below, they inquired of the neighbors. “And while Peter thought, the Spirit said unto him, Arise, get you down, and go, nothing doubting, for I have sent them.” (<!--<span class="stiki"></span>-->v. 19, 20.) And he does not say, For to this end did the vision appear unto you; but, “I have sent them. Then Peter went down” — this is the way the Spirit must be obeyed, without demanding reasons.
For it is sufficient for all assurance to be told by Him, This do, this believe: nothing more (is needed)— “Then Peter went down, and said, Behold, I am he whom you seek: what is the cause wherefore you have come?” He saw a soldier, saw a man: it was not that he was afraid, on the contrary, having first confessed that he was the person whom they sought, then he asks for the cause (of their coming); that it may not be supposed that the reason of his asking the cause, was, that he wished to hide himself: (he asks it) in order, that if it be immediately urgent, he may also go forth with them, but if not, may receive them as guests.
“And they said, etc. into his house.” This he had ordered them. Do not think he has done this out of contempt: not as of contempt has he sent, but so he was ordered. “And Cornelius was waiting for them, and had called together his kinsmen and near friends.” It was right that his kinsmen and friends should be gathered to him. But being there present, they would have heard from him (what had happened).
Source: Homilies on Acts (New Advent)