Rev. 16:12 –The sixth [angel] poured out his bowl on the great river Euphrates, and its water was dried up to prepare the way for the kings from the east. 13 Then I saw three unclean spirits like frogs [coming] from the dragon’s mouth, from the beast’s mouth, and from the mouth of the false prophet. 14 For they are spirits of demons performing signs, who travel to the kings of the whole world to assemble them for the battle of the great day of God, the Almighty. 15 “Look, I am coming like a thief. Blessed is the one who is alert and remains clothed so that he may not go naked, and they see his shame.” 16 So they assembled them at the place called in Hebrew Armageddon. (HCSB)
Its water was dried up
The Euphrates River figures prominently in both the sixth trumpet judgment and the sixth bowl judgment. As you may recall, in the sixth trumpet judgment four demons bound at the Euphrates are released to lead a vast army that kills a third of the human race. Here, in the sixth bowl judgment, the waters of the great river are dried up to make way for the “kings of the east.”
In 536 B.C., Cyrus the Persian devises a plan to divert the flow of the Euphrates River, which runs under the wall surrounding Babylon. This enables his soldiers to march under the wall, take Belshazzar by surprise and capture the city without serious resistance. It’s possible that John is drawing from this well-known historic event to prepare his readers for a swift and certain act of judgment, although it’s not necessary to interpret the drying of the waters literally. In fact, many commentators see the river as a symbol for political or religious boundaries, impediments to the advance of evil forces, or the geographic region from which many of Rome’s soldiers came to destroy Jerusalem in 70 A.D.
Some futurists, however, believe the Euphrates will indeed dry up, enabling a coalition of Eastern powers to sweep into the Holy Land. While the implication is that the water is dried up by an act of God, “the fact is that dams have been built across the Euphrates River in this [20th] century to divert water for irrigation so that there are times even today when there is little or no water in the Euphrates” (J.F. Walvoord, R.B. Zuck, The Bible Knowledge Commentary: An Exposition of the Scriptures, Rev. 16:12).
It’s worth noting the similarities between what happens here and what occurs in the crossing of the Red Sea and the march across the Jordan River as God’s people pass out of bondage and into the Promised Land. The miracle that Israel experiences in Old Testament times is now repeated in a negative sense, say preterists, as the first-century Jews who have rejected their Messiah are called into account for their national sin.