Cast off their clothes - Bishop Pearce supposes that shaking their upper garments is all that is meant here; and that it was an ancient custom for men to do so when highly pleased or greatly irritated; but it is likely that some of them were now actually throwing off their clothes, in order to prepare to stone Paul.
Threw dust into the air - In sign of contempt, and by way of execration. Shimei acted so, in order to express his contempt of David, 2 Samuel 16:13, where it is said, he cursed him as he went, and threw stones at him; or, as the margin, he dusted him with dust. Their throwing dust in the air was also expressive of extraordinary rage and vindictive malice. The apostle, being guarded by the Roman soldiers, was out of the power of the mob; and their throwing dust in the air not only showed their rage, but also their vexation that they could not get the apostle into their power. It is still used as a token of hostility and defiance. M. Denon, (Travels in Egypt, vol. iii. p. 98), on coming down the Nile to Cairo, stopped at the ancient city of Antinoe, to examine its ruins. "Being desirous of obtaining a view of the whole of these ruins, we ascended a little hill, and soon perceived the inhabitants of the modern village assembling behind an opposite eminence: scarcely had we come over against them than, supposing our intentions to be hostile, they called out for assistance, and threw dust into the air, in token of defiance. The alarm spread, and they began firing upon us."
Cast off their clothes - Their outer garments. Probably they did it now intending to stone him, Acts 7:58.
And threw dust into the air - As expressive of them abhorrence and indignation. This was a striking exhibition of rage and malice. Paul was guarded by Roman soldiers so that they could not injure him; and their only way of expressing their wrath was by menaces and threats, and by these tokens of furious indignation. Thus, Shimei expressed his indignation against David by cursing him, throwing stones at him, and casting dust, 2 Samuel 16:13.