Revelation 16:14

Here John identified the spirits as demons. The demons go out to the kings of the earth deceiving them to assemble their armies in Palestine for the battle of Armageddon. A deceiving spirit earlier lured King Ahab into battle (1 Kings 22:21-23). They will do this under the influence of Satan, the beast, and the false prophet. The demons persuade them, but their decision is something that God, the ultimate cause, puts in their hearts (Revelation 17:17).

It may also be the advancing army from the east that moves these kings to assemble for war. [Note: Moffatt, 5:447.] These kings from all over the world will gather to destroy Israel (cf. Psalms 2:1-3; Joel 2:11; Joel 3:2; Zechariah 14:2-3). Satan’s purpose in bringing all these soldiers into Palestine in the first place appears to be to annihilate the Jews. When Jesus Christ returns to earth, specifically to the Mount of Olives (Zechariah 14:1-4), they will unite in opposing Him. However God’s sovereign hand will be regulating Satan’s activities (Zechariah 14:2). This will not be the day of Satan’s triumph but that of the Lord God Almighty. He will show Himself supreme in this climactic battle (cf. Joel 2:31). The description of this battle follows in Revelation 19:11-16.

Gundry believed that the day of the Lord includes the battle of Armageddon but not the Tribulation. [Note: Gundry, p. 92.] Most premillennial interpreters believe this distinction lacks convincing support, and I agree with them.