Merchants of the earth weep and mourn over Babylon's fall, because no one buys their cargoes anymore, which is the source of their riches. These cargoes of luxurious things, which people now must do without, because it was Babylon's wealth that had made them rich.
John hears a voice telling the occupants of heaven, saints, apostles, and prophets to rejoice over Babylon's destruction, because God has judged her for the way she treated them.