Acts 22:23 - Ellicott's Commentary On The Whole Bible

Cast off their clothes, and threw dust into the air. — The latter gesture would seem to have been a natural relief, as with other Oriental nations, to the violence of uncontrolled passion. It may be, however, that the handfuls of dust were aimed at the Apostle as a sign of loathing (comp. Notes on Acts 18:6; Matthew 10:14); and if we take the English version, the “casting off” their outer garments looked very much like preparing for the act of stoning, as in Acts 7:58. The verb may, however, mean only that they “shook their garments,” as St. Paul had done in Acts 18:6, and so the two gestures might be parts of the same act. On the whole, the latter view seems the more probable.