The next part of the prophecy — "go, swift messengers, to a nation strong and vigorous" — (ibid., 2) — speaks of the disciples of the Savior, whom the prophecy calls "swift messengers" — in contrast to the Jewish ones mentioned by him, and by virtue of the fact that they are proclaimers of good tidings to all people.
Acts 28:23–24. And when they had appointed him a day, very many came to him at his lodging; and he expounded to them from morning till evening, teaching about the Kingdom of God, bringing testimonies and persuading them concerning Jesus from the Law of Moses and the Prophets. And some were convinced by his words, while others did not believe.
The Jews call faith in Christ a heresy. But even they testify that Christ is preached everywhere, although not all accept this preaching, and some of the Jews and Greeks even oppose it.
Acts 28:25. And being in disagreement with one another, they were departing, when Paul spoke the following words: well did the Holy Spirit speak to our fathers through the prophet Isaiah:
Observe how the Jews now plot against Paul: in Judea they were like tyrants, but here, even though rebuked by Paul, they dare say nothing against him, because his case was no longer subject to their authority.
"Well spoke the Holy Spirit." Here Paul opportunely strikes a blow against those who assert that the Holy Spirit is a person subservient to the Father, because he calls the Holy Spirit Lord, sitting "on a throne, high and lifted up," Whom Isaiah saw (Isa. 6:1), since the Holy Spirit is consubstantial with the Father and the Son and has equal authority with Them.
Acts 28:26–29. "Go to this people and say: By hearing you shall hear, and shall not understand; and seeing you shall see, and shall not perceive. For the heart of this people has grown dull, and their ears are hard of hearing, and their eyes they have closed, lest they should see with their eyes, and hear with their ears, and understand with their heart, and turn back, that I might heal them" (Isa. 6:9–10). "Therefore let it be known to you that the salvation of God has been sent to the Gentiles: and they will hear it. And when he had said these things, the Jews departed, having a great dispute among themselves.
They did this, he says, people who stopped their ears and closed their eyes, who "will not turn, so that I may heal them." This points to the strong impiety and stubborn aversion of these people. This is said in order to attract and dispose them, and to show that if they turn back, they will be healed.
"For the heart of this people has grown dull." This is said not in the sense that God, Who desires all to be saved and to come to the knowledge of the truth, contributes to their not seeing, as though He were zealous that they not hear; rather, we are accustomed to speaking this way about people who withdraw and do not wish to hear the words of salvation. Such a person flees and turns away so as not to hear the word that could convert him and restrain him from evil.
Acts 28:30–31. And Paul lived two whole years at his own expense and received all who came to him, preaching the Kingdom of God and teaching about the Lord Jesus Christ with all boldness unhindered.
Paul did not act like that Diogenes who dressed in rags and lived in a barrel, who amazed many with things in which they had no need whatsoever, yet brought benefit to no one. Paul did nothing of the sort, because he did not turn his gaze toward ambition. On the contrary, Paul dressed with every possible propriety, lived constantly in a house, and showed every care for decency, which the aforementioned cynic neglected, violating it publicly, living intemperately, and being carried away by a passion for glory. If anyone should undertake to seek the reasons for his dwelling in a barrel, he will find no other reason than vainglory alone. But Paul even paid for the lodging he occupied in Rome.