The following words are taken from Joel Beeke’s great commentary on The Revelation. At the end of the 9th chapter of the Apocalypse we read these incredible words:
Rev 9:20-21 The rest of mankind, who were not killed by these plagues, did not repent of the works of their hands nor give up worshiping demons and idols of gold and silver and bronze and stone and wood, which cannot see or hear or walk, (21) nor did they repent of their murders or their sorceries or their sexual immorality or their thefts.
Listen to what Beeke says about this:
The concluding verses of Revelation 9 present us with the greatest woe of all—the woe of ultimate impenitence: “And the rest of the men which were not killed by these plagues yet repented not of the works of their hands, that they should not worship devils, and idols of gold, and silver, and brass, and stone, and of wood: which neither can see, nor hear, nor walk: neither repented they of their murders, nor of their sorceries, nor of their fornication, nor of their thefts” (vv. 20–21).
Are you penitent and believing or impenitent and unbelieving? Every assault of Satan and every war in the world is a warning for you. The destructive forces and massive armies of sin prepare to destroy you. With this, as well as the countless sins that you are accumulating in your life, will you still refuse to repent before God? Let the fifth and sixth trumpets so frighten you that you flee to God and cry out for mercy.
God’s judgments will be terrible upon those who refuse to believe; only those whom He seals will escape His judgment. It will be dreadful if God must say of us at the end of our lives that despite all His plagues we did not repent of our idols or acts of hatred, sexual immorality, and greed. Though they are warned about this agony and destruction, unbelievers still refuse to repent of their wickedness before God. This is the tragedy of Revelation 9.
If you do not worship God and obey Him, you are choosing “death rather than life, darkness rather than light, bondage rather than freedom, guilt rather than peace, shame rather than honor, and Hell rather than Heaven.” The greatest of all woes is God’s judgment upon the spiritually impenitent, the spiritually dead: they will be cast into the darkness of the abyss forever.
Beeke, Joel. Revelation: The Lectio Continua: Expository Commentary on the New Testament (p. 220). Reformation Heritage Books. Kindle Edition.