John Calvin on Acts 19:17

17. There came fear. The fruit of that vengeance which God brought upon those who did wickedly abuse the name of Christ is this, in that they were all touched with reverence, lest they should contemn that doctrine, whose revenger the Lord hath showed by an evident token and testimony he would be, and they were brought to reverence Christ. For, besides that God doth invite us by all his judgments to come thus far, that they may terrify us from sinning, in this example peculiarly was the majesty of Christ set forth, and the authority of the gospel established. Wherefore, there is more heavy and grievous punishment prepared for deceivers, who, with their enchantments, profane the name of Christ wittingly, lest they promise to themselves that they shall escape unpunished for such gross sacrilege. Whereas he saith that it was made known to all men, it signifieth as much as commonly or everywhere. For his meaning is, that the matter was much talked of among the people, to the end the name of Christ might be made known to more men.

Acts 19:18-22

18. And many of those which believed came, confessing, and showing their works. 19. And many of those which used curious arts, bringing their books, burnt them before them all; and when they had cast the price of them, they found it fifty thousand pieces of silver. 20. So mightily grew the word of the Lord, and was confirmed. 21. And when these things were accomplished, Paul purposed in spirit, having passed over Macedonia and Achaia, to go to Jerusalem, saying, After that I have been there, I must also see Rome. 22. And when he had sent two of those which ministered to him into Macedonia, to wit, Timotheus and Erastus, he stayed for a time in Asia.