What does Revelation 9:15 mean?
Prior verses indicated these beings were "bound," meaning they are fallen angels, or demons. This verse reports that the four angels had been prepared precisely for the time of their release. The words, "the hour, the day, the month, and the year" are not intended to be added together into some exact amount of time. Rather, this expression means God had prepared them for this precise instant of their release—for this exact moment in history.The purpose of these demons' release was to kill one third of mankind. Daniel 12:1 predicts this terrible time. It states: "And there shall be a time of trouble, such as never has been since there was a nation till that time." Also, this level of catastrophe was part of what Jesus predicted, calling it a great tribulation. Matthew 24:21–22 records His words: "For then there will be great tribulation, such as has not been from the beginning of the world until now, no, and never will be. And if those days had not been cut short, no human being would be saved. But for the sake of the elect those days will be cut short."
Jesus' words are not entirely symbolic. The fourth seal judgment (Revelation 6:7–8) released the "pale" horseman who caused the death of one fourth of earth's people. This sixth trumpet judgment slays one third of those who survive, meaning the apocalypse has already killed half of the pre-tribulation population. Death on that scale, in only a few years, would eventually lead to human extinction, if not held in check by God.
Revelation 9:13–21 provides further insight into the assault by the northern invader. Earlier in chapter 9 we read about a horde of demonic locusts ascending from the bottomless pit. Now we read about two hundred million heavily armed cavalrymen, whose horses have heads like those of lions and tails like those of snakes. Four angels residing at the Euphrates allow the demonic army to advance across the river. The swarm of locusts described earlier may control or even possess these two hundred million cavalrymen. What follows is the annihilation of one third of humanity. However, the rest of humanity refuse to repent of their evil deeds, idolatry, murders, sorceries, or sexual immorality. Joel 2 and Ezekiel 38 also prophesy this northern army's invasion of Israel. Revelation 10 will provide another interlude between the judgments.
Revelation 9 tells us that under the fifth trumpet judgment John sees a star fall from heaven to earth. This ''star'' is Satan, and he is given the key to the bottomless pit. Using this key, Satan unleashes a plague of supernatural demons resembling locusts. They torment unbelievers for five months with such pain that people seek death unsuccessfully. They appear like horses prepared for battle, and they have a king, whose name is Apollyon, meaning ''Destroyer.'' Under the sixth trumpet judgment John sees four angels released from the Euphrates river. Their release coincides with a horde of two hundred million demonic mounted troops that kill a third of mankind. However, the survivors refuse to abandon their idolatry and to repent of their evil deeds.