v.10-11 Then the fifth angel poured out his bowl on the throne of the beast, and his kingdom became full of darkness; and they gnawed their tongues because of the pain. And they blasphemed the God of heaven because of their pains and sores, and did not repent of their deeds.
This “fifth judgment” is poured out upon the throne of the beast himself, causing his kingdom to become absolute and utter darkness.
Any number of catastrophes, including a nuclear blast, forest fires, oil fires, or volcanic eruptions could explain the sudden darkness. We don’t know but it most certainly fits what the prophet Joel describes will ultimately occur.
“And I will show wonders in the heavens and in the earth: blood and fire and pillars of smoke. The sun shall be turned into darkness, and the moon into blood, before the coming of the great and terrible day of the Lord” (Joel 2:30-31)
Yet, for all the turmoil, chaotic despair, and gnawing pain these plagues are causing, the people are so dark spiritually and morally that they continue to blaspheme God and do not repent (see also—Isa.60:2).
v.12-14 Then the sixth angel poured out his bowl on the great river Euphrates, and its water was dried up, so that the kings from the east might be prepared. And I saw three unclean spirits like frogs coming out of the mouth of the dragon, out of the mouth of the beast, and out of the mouth of the false prophet. For they are spirits of demons, performing signs, which go out to the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty.
This “sixth judgment” is poured out upon the Euphrates River.
This causes the river to dry up, thus preparing “the way” for the kings from the east (or more literally “the kings of the rising sun”). Moreover, in concert with the elimination of the Euphrates, comes the release of three unclean spirits who, through the performing of signs, awaken the kings of the earth to gather them for battle at Armageddon (see also—Rev.14:17-20).
It is interesting to note that a dam on the Euphrates in Turkey called the Ataturk Dam was completed in 1990 both to generate electricity and to irrigate the plains in the region. Seemingly, it can just as easily shut down the Euphrates.
v.15 “Behold, I am coming as a thief. Blessed is he who watches, and keeps his garments, lest he walk naked and they see his shame.”
This alert is given by Jesus to His people to be ready for Him. The same idiom is used elsewhere in the New Testament (Matt.24:42-44; Luke 12:35-40; 1Thess.5:2-4; 2Peter 3:10; Rev.3:3) and is always directed to believers, not to the world.
This does not refer to His Second Coming. That event will be known by the world; in fact the armies of the world actually gather together to make war with Him at His Return (Rev.19:19). The implication is that Christ will come for believers at an uncertain time by surprise, and therefore we must always remain in sober watchfulness.
This alert certainly surrounds the rapture of the church. For that event will happen in the twinkling of an eye and the world will know nothing of this until after it occurs (much like not knowing your house has been broken into until you discover things missing). The argument can be made that it also surrounds the Tribulation period and judgments in that the rapture will first occur then is followed by the Tribulation.