2 Samuel 16:13

And as David and his men went by the way, Shimei—cast dust— When the Consul whom Dr. Pococke attended entered Cairo, the Doctor tells us, "according to an ancient custom of state, a man went before, and sprinkled water on the ground to lay the dust." Every one knows the convenience of this practice in dry and hot countries; but I do not remember to have met with the mention of it anywhere else, as an eastern way of doing honour; yet if it was not barely a thing thought at that time convenient, but an ancient custom of state, the same causes might occasion it to be used in other countries; and if it had been used in Judea before the time of David, in the days of the judges and of Saul, it will explain Shimei's behaviour, and give it the greatest energy; who, in opposition to it, threw stones at the king, and dusted him with dust in the day of his affliction. He had been wont to be honoured by having people go before him to take care that the ground should be moistened, and no dust raised where he was to pass: Shimei did the reverse. This honour is not confined, however, to royalty: an English Consul was thus treated. Private persons were also thus dishonoured; the Jews clamoured against St. Paul in the temple, and threw dust. Acts 22:23. Observations, p. 287.