John condemns harlot Babylon for her luxury. The Greek word is strenos, which is used only once in the LXX, to describe the “complacency” of Sennacherib (2 Kings 19:28). The Hebrew term behind it is sha’anan, which describe the women of Jerusalem (Isaiah 32:9, 11), those who are at ease in Zion (Amos 6:1), the nations that are at ease (Zechariah 1:15). Babylon offends God not only because of her porneia, but because of her arrogant sense of security (Revelation 18:7).
Complacency comes along with wealth, or presumed wealth, not only for Babylon but for the Laodiceans (Revelation 3:17-18). So long as Babylon stays wealthy, she thinks she’s utterly secure, a queen who will never see mourning.
This was the sin of the Bible’s first fallen city, Sodom (it’s no accident that harlot Babylon is also “Sodom,” Revelation 11:8). Sodom was a city of porneia, but also complacent wealth and lack of compassion for the poor (Ezekiel 16:49).
Babylon’s boast that she will never see mourning is taken from Isaiah 47, but it’s an ironic boast, because in Isaiah it is the boast of a Babylon that has been stripped and sits in the dust. Invulnerable as she looks, she is doomed. Complacent cities won’t stand for long.
Jerusalem is a different sort of city, characterized by compassion rather than complacency. Jerusalem is not only a faithful bride, but a nurturing mother, who feeds her children rather than devouring them.