The prophecy which commences this chapter occupies the first ten verses. That it relates to Babylon is apparent from Isaiah 21:2, Isaiah 21:9. The object is to foretell the destruction of that city by the Medes and Persians, and the design is the same as in the more extended and minute description of the same event in Isaiah 13; Isaiah 14: Whether it was delivered at the same, or at another time, cannot be determined from the prophecy. The purpose, however, of the prophecy is the same as there - to give consolation to the Jews who should be carried captive to that city; to assure them that Babylon would be destroyed, and that they would be delivered from their long and severe bondage. This is indicated in a brief and graphic manner in Isaiah 21:10.
This oracle, or ode, is one of singular beauty. It is distinguished for its brevity, energy, and force, for the variety and the rapidity of the action, and for the vivid manner in which the events are made to pass before the mind. It is the language of strong excitement and of alarm; language that expresses rapid and important movements; and language appropriate to great vigor of conception and sublimity in description. In the oracle the prophet supposes himself in Babylon, and the events which are described are made to pass rapidly in vision (see the Introduction, Section 7, 4) before him. He first sees Isaiah 21:1 the dreadful storm coming at a distance (the hostile armies), approaching like a whirlwind and threatening destruction to everything in its way. He then Isaiah 21:2 hears God’s direction to the invading armies; represents himself as made acquainted with the design of the vision, and hears the command of God to Elam (Persia) and Media to go up and commence the siege.
Regarding himself as among the exiles in the midst of Babylon, he Isaiah 21:3-4 describes himself as deeply affected in view of this sudden invasion, and of the calamities that were coming upon Babylon. In Isaiah 21:5, he describes the state of the Babylonians. They are represented, first as preparing the table, making ready for feasting and revelry, setting the watch on the watch-tower, and giving themselves up to dissipation; and secondly, as suddenly alarmed, and summoned to prepare for war. He then (Isaiah 21:6-9 declares the way in which the princes of Babylon would be roused from their revelry. But it is described in a very remarkable manner. He does not “narrate” the events, but he represents himself as directed to appoint a watchman Isaiah 21:6 to announce what he should see. That watchman Isaiah 21:7 sees two chariots - representing two nations coming rapidly onward to execute the orders of God. So rapid is their approach, so terrible their march, that the watchman cries out Isaiah 21:9 that Babylon is fallen, and will be inevitably destroyed. The prophecy is then closed Isaiah 21:10 by an address to the afflicted Jews whom God had ‘threshed,’ or punished by sending them captive to Babylon, and with the declaration that this was intended by the Lord of hosts to be declared unto them. The whole design of the prophecy, therefore, is to console them, and to repeat the assurance given in Isaiah 13; Isaiah 14, that Babylon would be destroyed, and that they would be delivered from bondage.