What does Revelation 19:21 mean?
The armies that followed the beast in his battle against Christ meet a fatal end. The sword from Christ's mouth slays them. Since the sword represents the Word of the Lord, it is safe to say that just a word from our Lord is sufficient to snuff out the lives of the beast's numerous soldiers. The "sword" has two edges (Revelation 1:16). It can save those who choose to believe in Jesus as Savior or condemn those who reject Him (Hebrews 4:12). The number of the slain soldiers is so numerous that all the vultures that are called to "the great supper of God" (Revelation 19:17) gorge themselves on the dead bodies. Of course, the slain soldiers experience not only physical death but also eternal death, as Revelation 20:11–15 explains.Belief in the existence of hell and eternal suffering is unpopular with certain religious teachers. They would rather believe that everyone goes to heaven eventually, or they choose to believe in the annihilation of the wicked. However, the Bible is clear; hell is real and those who go to that dreadful place experience real suffering forever. The first to experience that torment, even before the millennial kingdom, are the Antichrist and the False Prophet (Revelation 19:19–20).
This victory sets up Christ's thousand-year reign on earth, described in chapter 20.
Revelation 19:11–21 presents one of Scripture's most spectacular moments of victory: the second coming of Jesus Christ. In this event, Christ returns to earth at the close of the tribulation. At His first coming to earth, Jesus appeared as a baby and sacrificial Savior. This time, He arrives as King of kings and Lord of lords. Many prior Scriptures prophesied this epic day of victory (Matthew 25; Zechariah 14:1–4; 2 Thessalonians 2:7–12; Hebrews 9:27–28; Jude 1:14–15). Christ arrives in a blaze of glory, obliterating His enemies single-handedly, at the head of the armies of heaven. The Antichrist and False Prophet become the first two cast into the lake of fire, ushering in the beginning of Christ's millennial reign on earth.
Revelation 19 begins with a multitude in heaven singing a doxology to God. He is praised for judging religious Babylon and avenging the martyrs. They are joined by the twenty-four elders (Revelation 4). Voices cry out joyfully that the Lord reigns and the marriage supper of the Lamb is ready. Then, John sees heaven open and observes Jesus—now coming as the glorious and invincible King of kings and Lord of lords—as He descends from heaven to execute judgment. The armies of earth gather to battle the Lord. The battle concludes with the Antichrist and False Prophet being thrown into the lake of fire and the graphic slaughter of their followers.