The problem for Isaiah, however, is that the filth and corruption was not outside Jerusalem, it was in it, in the hearts and on the lips of his people. That was the reason for all the invasions of Assyria and Babylonia. The kings of the north would be a purifying fire that would purge the sin from his people. There would be such a military defeat that only one in seven men would survive, and be fought over by the surviving women. Isaiah believed that the survivors would be so purified that they would make a just society, one that worshiped God alone, and attract the loving protection of their God forever.