Matthew Henry Commentary Revelation 18:20-24

"Rejoice over her, thou heaven, and ye saints, and ye apostles, and ye prophets; for God hath judged your judgment on her. And a strong angel took up a stone as it were a great millstone and cast it into the sea, saying, Thus with a mighty fall shall Babylon, the great city, be cast down, and shall be found no more at all. And the voice of harpers and minstrels and flute-players and trumpeters shall be heard no more at all in thee; and no craftsman, of whatsoever craft, shall be found any more at all in thee; and the voice of a mill shall be heard no more at all in thee; and the light of a lamp shall shine no more at all in thee; and the voice of the bridegroom and of the bride shall be heard no more at all in thee: for thy merchants were the princes of the earth; for with thy sorcery were all the nations deceived. And in her was found the blood of prophets and of saints, and of all that have been slain upon the earth." — Revelation 18:20-24 (ASV)

What is a cause for rejoicing to the servants of God on earth, is also a cause for rejoicing to the angels in heaven. The apostles, who are honored and daily worshiped at Rome in an idolatrous manner, will rejoice in her fall. The fall of Babylon was an act of God's justice.

And because it was a final ruin, this enemy would never trouble them anymore; they were assured of this by a sign. Let us take warning from the things which brought others to destruction, and let us set our affections on things above, when we consider the changeable nature of earthly things.