Great question - how to translate Rev 16:16 - should it be translated "he gathered", or, "they gathered".
Grammatically, the verb συνήγαγεν is 3rd person singular and so it should strictly be translated "he gathered". However, note V13, 14 -
And I saw three unclean spirits that looked like frogs coming out of
the mouths of the dragon, the beast, and the false prophet. These
are demonic spirits that perform signs and go out to all the kings
of the earth, to assemble them for battle on the great day of God
Note that in V13 & 14, it is the three unclean frog who are demonic spirits (plural) who do the gathering. So why the singular "he gathered" in V16? Note the comments of Albert Barnes:
And he gathered them together - Who gathered them? Prof. Stuart renders it "they gathered them together," supposing that it refers to
the "spirits" - πνέυματα pneumata - in Revelation 16:13, and that
this is the construction of the neuter plural with a singular verb. So
DeWette understands it. Hengstenberg supposes that it means that God
gathered them together; others suppose that it was the sixth angel;
others that it was Satan; others that it was the beast; and others
that it was Christ. See Poole's Synopsis, in loco. The authority of
DeWette and Prof. Stuart is sufficient to show that the construction
which they adopt is authorized by the Greek, as indeed no one can
doubt, and perhaps this accords better with the context than any other
construction proposed. Thus, in Revelation 16:14, the spirits are
represented as going forth into the whole world for the purpose of
gathering the nations together to the great battle, and it is natural
to suppose that the reference is to them here as having accomplished
what they went forth to do.
OK, this is the analysis of Prof Stuart as quoted by Barnes, and most modern versions appear to agree, eg, NIV, NLT, ESV, BSB, NKJV, NASB, CSB, HCSB, ASV, ISV, etc, presumably on the basis of the explicit reference in V13 & 14 as quoted above.
However, there is another possible explanation if we notice the classic chain of command/authority:
- the three evil spirits like frogs appear to be the ones doing the gathering of the kings of the whole earth, Rev 13:14
- The three evil spirits like frogs come from the mouths of, and thus are directed by, the dragon, the (sea) beast and the false prophet = the land beast of Rev 13:12-18, 19:20, etc.
- This beast trinity (dragon, sea beast and land beast/false prophet) is created by the dragon, see Rev 12:17, 13:1 where the dragon, who is very angry (Rev 12:17) stands on the shore of the sea (the border between the land and sea) and calls up two more monsters to aid him in the fight with the woman - the sea beast (Rev 13:1-10) and the land beast (Rev 13:12-17)
- the Dragon, The Devil, Satan, the ancient serpent (Rev 12:9), is the beast that finally directs the other two beats. .
Thus, it appears that Satan directs the beast trinity and the beast trinity direct the spirits like frogs who gather the kings of the earth. That is, while the three frogs gather the kings, they ultimately act at the behest of Satan. Thus, the text says, "he [Satan] gathered".
Thus, the great battle of Armageddon (V16) is between:
- Satan, his beast trinity, the evil spirits and the kings of the earth
- God and the armies of heaven (Rev 19:11-16) who are dressed in white robes (Rev 19:14). These heavenly armies are led by none other than the "Word of God" (Rev 19:13) who is called: "KING OF KINGS AND LORD OF LORDS", with a robe dipped in blood and eyes like blazing fire (cf Rev 1:14), riding the white horse, and thus is Jesus Christ.
This battle is finally won by the armies of heaven as per Rev 19:17-21.