Isaiah 20-24 speaks about the judgment of the nations. It was written because the people of God are tempted to look out, as if from a high mountain, to the nations for direction and salvation even though those nations will be judged by God. With respect to the nations we should see ourselves as in the valley of vision -- a valley where there is nowhere to look but up and it is a valley of vision because God revealed Himself to us in visions like Isaiah's. And so we should not be looking to the false religions of the nations for direction and salvation when we have true revelation from God. "The oracle concerning Dumah" is about Edom where Dumah means silence -- and so we should not be looking out to the nations for direction because they are silent rather than inquiring of God. Babylon, "the oracle concerning the wilderness of the sea" was the great land power representing world government and Tyre was the great sea power representing big business. We are not to look to government or to the marketplace (of the nations, individually or collectively) for direction and salvation either. We are to turn and look up.