John Calvin Commentary Acts 19:27

"and not only is there danger that this our trade come into disrepute; but also that the temple of the great goddess Diana be made of no account, and that she should even be deposed from her magnificence whom all Asia and the world worshippeth." — Acts 19:27 (ASV)

Not only this part. This is first handled in a disorderly way, in that Demetrius is concerned about religion after other matters; for nothing is more absurd than to prefer the belly to the goddess; but even this is also futile, in that he pretends that the worship of Diana is in danger.

For if he had suffered no loss from Paul’s teaching, he would have sat quietly at home; he would neither have given thought to the worship of Diana, nor would he have troubled others. What, then, is the reason he is so diligent and so earnest in his business? It is simply this: because his own livelihood was threatened. And because he saw that he and his associates had no honest or credible reason to cause a disturbance, he attempts to gloss over the matter with some other pretext.

Therefore, so that he may cover the shame of his wicked deed, he cloaks it with the plausible title of religion. Thus, the wicked, however stubbornly they strive against God, yet they impudently gather seemingly honest excuses here and there. But God does not allow Himself to be mocked, but rather pulls them out of their subterfuges.

No other witness is needed to refute Demetrius’ hypocrisy, because he cuts his own throat with his own words when he betrays the sorrow he felt because of the loss he sustained. The Papists are in a similar state today: they boast loudly that they are patrons of the Catholic faith and of the holy mother Church, but when they have spoken this way about their zeal, in the actual handling of the matter, they openly reveal the smell of their kitchens.

But if we desire to handle the cause of godliness purely and earnestly, let us forget our own advantages, so that the glory of God may have the chief place. For the appearance of profit so binds all our senses with enticements that, even if we wander through all kinds of wickedness, we still flatter ourselves as long as we are determined to provide for our own advantage.

Whom all Asia and the world doth worship. It seems to Demetrius an unfitting thing that Diana’s majesty should be brought to nothing, whom all the world reveres and worships. And this is a common subterfuge for all superstitious people: to claim the agreement of the multitude.

But true religion requires a more steadfast foundation than the will and pleasure of men. There is nothing that today more holds back the simple and ignorant than that they dare not cast off (such ancient) errors as are commonly accepted everywhere. Because they falsely imagine that what pleased many—however foolishly and rashly—is to be considered lawful.

For this reason, they are not afraid to boldly set the mere name of custom against God Himself. But the Lord prescribes another kind of rule for us, namely, that being content with His authority alone, we are to pay no regard either to the opinion of men, nor to our own advantage, nor to the custom of many nations.