9:14 one saying to the sixth angel who had the trumpet, "Release the four angels who are bound at the great river Euphrates."
one saying to the sixth angel who had the TRUMPET,
The sound (speaker) was one of the incense altar horns (see previous verse) to the sixth angel. Some commentators think this is Christ Himself speaking, but it could be one of the four living creatures.
"Release the four angels who are bound at the great river Euphrates."
These are four major angels working for the devil; this is almost like the devil always tries to do one better than the Triune God. It is time for the 'judgment of the great day' (Jude 6) for these angels. Looking at the map, one sees that there are four present day countries through which the Euphrates flows: Turkey, Syria, Iraq, and Kuwait. Perhaps these FOUR angels are symbolic of these four countries. None of these countries are Israel's "friends".
The Euphrates River is prominent throughout the Bible. It was one of the Garden of Eden rivers, Genesis 2:10-14. Its source is not from rain but some undergound aquafer, Genesis 2:5-6. At Noah's time, the Euphrates source may have been one of the fountains of the great deep, Genesis 7:11.
At the Euphrates River, all of sin is first manifested. The apple is eaten; there is hatred; the first murder is committed; and the first martyr is listed. This place is demon possessed. As a curious sidelight, the King James Version states these angels are bound IN the river, while this version says AT the river.
'IN the river' makes more sense, when one thinks of the demoniac who was cured in Luke 8:26-39. The demons begged not to be sent to the abyss but rather into the swine. When the swine drown, the demons were left in the water. It is interesting from a spiritual viewpoint how God uses the physical world, the devils playground, as a spiritual container. And only at the granted permission can these demons work on apostate Jews and non-believer Gentiles. God could have used the mighty archangels Gabriel or Michael to do the job, but it is more appropriate this way for the devil and his angels to do the murdering of 1/3 of mankind as seen in the next verse.
Note that not all water contains demons. Christ says He is the Living Water. There is a River of water of LIFE in Revelation 22:1.