But when they knew - When they perceived or ascertained.

That he was a Jew - There was a general prejudice against the Jews. They were disposed to charge the whole difficulty on Jews - esteeming Christians to be but a sect of the Jews. They were, therefore, indiscriminate in their wrath, and unwilling to listen to any defense.

With one voice - Unitedly, in one continued shout and clamor.

About the space of two hours - The day, from sunrise to sunset, among the Greeks and Romans, was divided into twelve equal parts, John 11:9. An hour, therefore, did not differ materially from an hour with us. It is not at all improbable that the tumult would continue for so long a time, before it would be possible to allay the excitement.

Cried out ... - This they at first did to silence Alexander. The shouting, however, was continued in order to evince their attachment to Diana, as would be natural in an excited and tumultuous mob of pagan worshippers.

But when they knew that he was a Jew,.... And so equally an enemy to their idolatry, as Paul and his companions were, whether he was a Christian or not.

All with one voice about the space of two hours cried out; all that were in the theatre lift up their voices at once to prevent Alexander's apology, or at least its being heard; and which they continued about two hours, which was a long time to keep hallooing out,

great is Diana of the Ephesians; See Gill on Acts 19:28.

With one voice cried out

The reverberations of their voices from the steep rock which formed one side of the theatre must have rendered their frenzied cries still more terrific.

{9} But when they knew that he was a Jew, all with one voice about the space of two hours cried out, Great is Diana of the Ephesians.

(9) Instead of reason, the idolaters are sufficiently contented with their own madness and outcries, and those are the greatest defence that they have.

19:34 But when they knew that he was a Jew - And consequently an enemy to their worship of images; they prevented him, by crying, Great is Diana of the Ephesians.

34. But when they knew he was a Jew, all with one voice, for the space of two hours, cried out, Great is Diana, &c.-The very appearance of a Jew had the opposite effect to that intended. To prevent him obtaining a hearing, they drowned his voice in one tumultuous shout in honor of their goddess, which rose to such frantic enthusiasm as took two hours to exhaust itself.

19:32-41 The Jews came forward in this tumult. Those who are thus careful to distinguish themselves from the servants of Christ now, and are afraid of being taken for them, shall have their doom accordingly in the great day. One, having authority, at length stilled the noise. It is a very good rule at all times, both in private and public affairs, not to be hasty and rash in our motions, but to take time to consider; and always to keep our passions under check. We ought to be quiet, and to do nothing rashly; to do nothing in haste, of which we may repent at leisure. The regular methods of the law ought always to stop popular tumults, and in well-governed nations will do so. Most people stand in awe of men's judgments more than of the judgement of God. How well it were if we would thus quiet our disorderly appetites and passions, by considering the account we must shortly give to the Judge of heaven and earth! And see how the overruling providence of God keeps the public peace, by an unaccountable power over the spirits of men. Thus the world is kept in some order, and men are held back from devouring each other. We can scarcely look around but we see men act like Demetrius and the workmen. It is as safe to contend with wild beasts as with men enraged by party zeal and disappointed covetousness, who think that all arguments are answered, when they have shown that they grow rich by the practices which are opposed. Whatever side in religious disputes, or whatever name this spirit assumes, it is worldly, and should be discountenanced by all who regard truth and piety. And let us not be dismayed; the Lord on high is mightier than the noise of many waters; he can still the rage of the people.