And they cast dust on their heads,.... As the seafaring men on account of Tyre, Eze 27:30 this was a gesture used in mourning when persons were in afflicted and distressed circumstances, denoting disorder, confusion, and debasement; see Jos 7:6 and cried, weeping and wailing, saying, alas, alas! that great city; as in Rev 18:10 so it was once, though now in flames: wherein were made rich all that had ships in the sea; not only the merchants of the earth, as in Rev 18:3 the cardinals, archbishops, and bishops, but the governors of religious houses; these accumulated great wealth to themselves, and got the best of lands into their possession for the use and support of their abbeys and monasteries: by reason of her costliness; or costly things; pardons, indulgences, absolution, saying Mass, and praying souls out of purgatory, all which are costly, and hereby these traders have been enriched; and now the remembrance of these things, of which they will be deprived, will affect and grieve them, as well as the suddenness of Rome's ruin: for in one hour is she made desolate; her judgment come, and her riches come to nought, Rev 18:10.