Isaiah now addresses the pagan enemies of Israel, the Philistines. They had been conquered by the Jewish armies a few years before, but since the Assyrians were already marauding the Mediterranean coasts as well as the mountains of Judah, the Philistines had asserted their independence. But Isaiah warns them not to rejoice just because they don't have to pay tribute to Jerusalem any more, because the brutal Assyrians will come out of the north and raid the plains of the Philistines unmercifully. Isaiah says the day will come when all of the traditional enemies of the Jews along the Philistine coasts will be obliterated and the Lord will eventually make it a place of peace and prosperity when he sets up Zion.