This connection (between Rev 17 and 16:12-21) is signaled in the very first verse of chapter 17, ESV: “Then one of the seven angels who had the seven bowls came and said to me. . . .” This is a clear connection between chapter 17 and the content of chapter 16. But the question remains: Which of the seven bowl angels is interacting the Seer of Patmos here? A clue to the answer lies in the fact that the angel’s message has something to do with water: “Come, I will show you the judgment of the great prostitute, who is seated on many waters” (Rev 17:1, ESV). Three of the bowl-plagues have something to do with water. The second bowl falls on the sea (Rev 16:3), the third bowl falls on the rivers and springs (Rev 16:4-7), and the sixth bowl falls on the Euphrates River (16:12). Which of the three bowl-angels is the one we encounter in Revelation 17? Since the waters of verse 1 are associated with the great prostitute, and she is later defined as Babylon the great (Rev 17:5), the angel of the sixth bowl (the one associated with the drying up of the Euphrates River) is the one in view when you get to 17:1.

This makes sense in light of the Old Testament background to Revelation 17. The “many waters” is a striking verbal parallel to Jeremiah 51:13. There, Babylon is addressed as “you who dwell by many waters”. Ancient Babylon was a twin city located in the midst of an extremely dry desert. Its “many waters”, therefore, can only be a reference to the mighty Euphrates River, that passed through the very center of the ancient city (cf. Jer 50:33-38; 51:36). So I think I know that Revelation 17 is closely related to the sixth bowl-plague, in which the Euphrates River is dried up.

The parallel with Revelation 16 is also extend to the seventh bowl plague (Rev 16:17-21). The immediate introduction to the Babylon visions of chapters 17 and 18 is in 16:19: “God remembered Babylon the Great.” The details of what happens when God “remembers” Babylon are found in Revelation 17 and 18. In addition, the battle of Armageddon in 16:16 finds its counterpart in Revelation 17:14, where the ten horns, the counterpart to the “kings of the whole world” (Rev 16:14, ESV), make war with the Lamb. So I think I know that Revelation 17 is an elaboration of the sixth and seventh bowl-plagues in chapter 16.