9:13,14 SIXTH TRUMPET, SECOND WOE
“And the sixth angel sounded, and I heard a voice from the four horns of the golden altar which is before God, saying to the sixth angel who had the trumpet, ‘Release the four angels who are bound at the great river Euphrates” (Revelation 9:13,14).
“The golden altar which is before God” is a reference to the altar of incense that was in the first room of the sanctuary, just in front of the veil that separated it from the
Ironically, from this place of intercession, covered by the blood of countless sacrifices, comes the cry to “release the four angels which are bound at the great river
The first stage is introduced in Chapter seven. As the 144,000 are about to be sealed, John “saw four angels standing at the four corners of the earth, holding the four winds of the earth that the wind should not blow on the earth, on the sea, or on any tree” (Revelation 7:1). But when the 144,000 had been sealed, the angel with the golden censer “threw it to the earth,” and the four winds were released. The very earth, sea and trees that had been protected were now destroyed in the first three trumpets.
With the fifth trumpet God makes a further release—the “star fallen from heaven to the earth…was given the key to the bottomless pit” (Revelation 9:1), and the locust army came forth to torture (but not kill) men for five months. Finally, with the sixth trumpet “the four angels which are bound at the great river
 Satan has already revealed his name or character in this chapter as Abaddon (Hebrew) or Apollyon (Greek), both of which mean "destroyer (Revelation 9:11).
 Chapter 11 presents the murder of the two witnesses. We will see that this is Satan’s attempt to destroy the 144,000. The same attempt is shown in chapter 13, expanding the details to show how Satan will use the beast from the sea and the beast from the earth to persecute God’s people through the image, mark and number of the beast and the death decree against “as many as would not worship the image of the beast” (Revelation 13:15).