When the sixth trumpet sounds, an angel next to the golden altar in the heavenly temple of God commands the
angel of the sixth trumpet to release of four bound angels at the Euphrates River.
In contrast to the fifth trumpet which initiates an angel to go unlock the abyss
(Rev 9:1), there is no mention of how the angel with the sixth trumpet
releases the four bound angels at the Euphrates River.
While the location of the four bound angels is uncertain, it is likely not the abyss.
When the Bible speaks of confined or bound angels, it is always in the context of fallen evil
angels (Luke 8:26-31; Matt 8:28-32;
2 Peter 2:4; Jude 1:6-7).
Just as with the fifth trumpet, God uses evil demonic instruments to carry out His judgment. Here the four bound
fallen evil angels serve a divine purpose.
God's scheduled the release of the four bound angels to commence at the exact hour of a precise
day of a certain month and of a specific year (Rev 9:15).
The four bound angels were limited to kill 1/3 of the population at that time. In consideration
of the fourth seal, in which 25% of the population was killed, the death of 1/3 of the surviving 75% leaves at most
50% of the original population before the tribulation began.
How human beings are killed is worth noting:
A third of mankind was killed by these three plagues, by the fire and the smoke and the
brimstone which proceeded out of their mouths. For the power of the horses is in their mouths and in their tails;
for their tails are like serpents and have heads, and with them they do harm.
The riders did not kill anyone.
The apostle John observes that after the four bound angels complete their task of carrying out God's judgment,
the surviving human beings, at most 50% of the original population before the tribulation, do not recognize that
the plagues confirm the existence of God and are unrepentant.
The rest of mankind, who were not killed by these plagues, did not repent of the works
of their hands, so as not to worship demons, and the idols of gold and of silver and of brass and of stone and
of wood, which can neither see nor hear nor walk; and they did not repent of their murders nor of their sorceries
nor of their immorality nor of their thefts. (Rev 9:20-21).
As in the case of Pharaoh, when a heart is so hard, including those who profess a faith but in
reality lack one, then God uses "plagues" to exact His judgment of death.
If you are not careful to observe all the words of this law which are written in this book,
to fear this honored and awesome name, the Lord your God, then the Lord will bring extraordinary plagues on
you and your descendants, even severe and lasting plagues, and miserable and chronic sicknesses. He will
bring back on you all the diseases of Egypt of which you were afraid, and they will cling to you. Also every
sickness and every plague which, not written in the book of this law, the Lord will bring on you until you
are destroyed. (Deut 28:58-61)