Isaiah 21:9
6 For this is what the Lord has told me:“Go, post a guard! He must report what he sees. 7 When he sees chariots, teams of horses, riders on donkeys, riders on camels, he must be alert, very alert.” 8 Then the guard cries out: “On the watchtower, O Lord, I stand all day long; at my post I am stationed every night. 9 Look what’s coming! A charioteer, a team of horses.” When questioned, he replies, “Babylon has fallen, fallen! All the idols of her gods lie shattered on the ground!” 10 O my downtrodden people, crushed like stalks on the threshing floor, what I have heard from the Lord of Heaven’s Armies, the God of Israel, I have reported to you.
Revelation 18:2
1 After these things I saw another angel, who possessed great authority, coming down out of heaven, and the earth was lit up by his radiance. 2 He shouted with a powerful voice:“Fallen, fallen, is Babylon the great! She has become a lair for demons, a haunt for every unclean spirit, a haunt for every unclean bird, a haunt for every unclean and detested beast. 3 For all the nations have fallen from the wine of her immoral passion, and the kings of the earth have committed sexual immorality with her, and the merchants of the earth have gotten rich from the power of her sensual behavior.”
Notes and References
"... The first section, verses 1–3, though often referred to as a funeral dirge or lament, is in fact a prophetic taunt song, though the latter is very probably a development of the former with the addition of a mocking tone (Eissfeldt, Introduction, 91); the victory song is also similar in that it incorporates themes from the taunt song. The angel serves as the leader of the ritual lament by making a public announcement of the death, a formal feature of ancient Israelite ritual laments (Jahnow, Leichenlied, 101, 138, 167). Taunt songs have no fixed form but are characterized by derision and joy over the (past, present, or future) misfortunes and shortcomings of others (see 1 Samuel 17:43, 44; Jeremiah 22:14–15; Isaiah 23:15–16). In Isaiah 37:22–29, for example, Hezekiah taunts Sennacherib. Taunt songs were taken up by Old Testament prophets for deriding the enemies of Israel and announcing their downfall (Isaiah 23–24, 47; Jeremiah 50–51; Ezekiel 26–27). This taunt consists first of an angelic announcement anticipating the fall of Babylon (verses 1–3). The opening words, 'Fallen, fallen is Babylon the great', are derived from Isaiah 21:9, yet the form of 18:1–3 is closer to Amos 5:1–3 (Jahnow, Leichenlied, 219), which is also cast in the form of the funerary lament, where the initial announcement of the fall of Israel is followed by a clause providing the reason for that fall ..."
Aune, David E. Word Biblical Commentary: Revelation 17-22 (p. 136) Word Books, 1998