Matthew Henry on Revelation 18:20-24

That which is matter of rejoicing to the servants of God on earth, is matter of rejoicing to the angels in heaven. The apostles, who are honoured and daily worshipped 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 should never molest them any more; of this they were assured 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.