By Dr. Tony Garland
Many conclude that the Harlot (Rev. 17) represents a religious system, whereas the city (Rev. 18) represents a commercial system. This view holds that what is said concerning the Harlot, and the very fact that she is said to be a Harlot, necessitates a purely religious role for her. Conversely, the commercial emphasis of Revelation 18 speaks more of a commercial system and a city. An unfortunate contributor to this separation into two parts is the chapter division between Revelation 17 and 18 which masks the unity of the entire passage. Since chapter divisions are not part of the inspired text, we need to be cognizant of their placement and the implicit effects they have on our interpretation. In the case of Revelation 17 and 18, it is true that Revelation 17 speaks more of the spiritual aspects of the Harlot. Similarly, Revelation 18 emphasizes commercial aspects. But this is not the full story because both chapters emphasize both aspects and overlap to a much greater degree than many interpreters are willing to admit. 
Revelation 17, while speaking of her harlotry, abominations, and being drunk with the blood of the martyrs of Jesus, also relates her great commercial wealth: "arrayed in purple and scarlet, and adorned with gold and precious stones and pearls, having in her hand a golden cup" (Rev. 17:4). Moreover, Revelation 18 speaks of her spiritual aspects: "For all nations have drunk of the wine of the wrath of her fornication, the kings of the earth have committed fornication with her" (Rev. 18:3) and "for by your sorcery all the nations were deceived. And in her was found the blood of prophets and saints, and of all who were slain on the earth" (Rev. 18:24). When the city of Babylon is finally overthrown, as predicted by the angel (Rev. 18:21), it is said, "He has judged the great harlot who corrupted the earth with her fornication; and He has avenged on her the blood of His servants shed by her" [emphasis added] (Rev. 19:2).
The question is, how different from the Babylon of chapter 17 is the Babylon of chapter 18? Undoubtedly the city is the same in both instances. Both have the name "Babylon the great" (Rev. 17:5; 18:2). Both are guilty of fornication (Rev. 17:1, 2, 4, 5, 16; 18:3) and of causing the kings of the earth and the earth-dwellers to imbibe of the wine (of the anger) of the city's fornication (Rev. 17:2; 18:3). The destiny of both is to be burned with fire (Rev. 17:16; 18:8, 9, 18) and to become an utter desolation (Rev. 17:16; 18:17, 19). In both chapters Babylon is "the great city" (Rev. 17:18; 18:10, 16, 18, 19, 21) and wears the apparel and adornment of a harlot (Rev. 17:4; 18:16). Both are responsible for the martyrdom of the faithful (Rev. 17:6; 18:20, 24 [cf. 19:2]). 
We also note that in the prediction of Babylon's demise by the flying angel there is not the slightest intimation of two systems or two destructions. Moreover, in the angel's description of Babylon, he calls it a "great city" (commercial) which is guilty of "fornication" (spiritual idolatry) (Rev. 14:8). There the self-same Babylon is described using both commercial and spiritual attributes. This unity is also evidenced under the seventh bowl where "Babylon was remembered before God, to give her the cup of the wine of the fierceness of His wrath" (Rev. 16:19). Only one Babylon is in view and its destruction is associated with a single judgment—the pouring forth of the last bowl of the wrath of God. We see no evidence of a separate judgment for the Harlot and a subsequent judgment of the city—as if they were two different entities.
Another factor favoring the unity of Revelation 17 and 18 is the announced mission of the angel sent to John: "I will show you the judgment of the great harlot who sits on many waters" (Rev. 17:1). This angel is with John from Revelation 17:1 throughout both chapters and speaks to him again in Revelation 19:19.  The act of showing John the judgment (singular) of the great harlot (singular) spans Revelation 17:1 through Revelation 19:4. The same event is in view the entire time. The angel gives not the slightest indication that John is being shown two entities and two destructions.
If we look at these two chapters carefully [Rev. 17 and 18], we fail to find the distinction so persistently affirmed. Someone states a thing as a fact; and then others think they see it. There is no such thing as "Mystic Babylon." The Babylon mentioned in chapter 17 is the same as that in chapter 18. It is the "Woman" which is a secret symbol or sign. But that means only that we are not to take it literally as a woman, but as "that great city," as is explained in [Rev. 17:18]. 
The idea that the Harlot is something other than the city of Babylon is difficult to maintain if Scripture alone is our guide. The Harlot is called a city (Rev. 17:18) while the city is described as a harlot (Rev. 18:3, 9, 23-24) and called "the great harlot" (Rev. 19:2). The Harlot is that great city Babylon!
 "A strong exegetical case can be made to support the proposition that Revelation 17 and 18 should be viewed as a unit speaking of one Babylon rather than two separate units speaking of two Babylons. The notion of viewing Revelation 17 and 18 as a unit is buttressed by noting the similarities between the chapters. Both chapters refer to Babylon as having the same name (Rev. 17:5; 18:2), holding a cup (Rev. 17:4; 18:6), fornicating with kings (Rev. 17:2; 18:3), being drunk with the wine of immorality (Rev. 17:2; 18:3), persecuting believers (Rev. 17:6; 18:24), experiencing destruction by fire (Rev. 17:16; 18:8), and experiencing destruction by God (Rev. 17:17; 18:5, 8)."—Andy Woods, What is the Identity of Babylon In Revelation 17-18?.
 Robert L. Thomas, Revelation 8-22 (Chicago, IL: Moody Press, 1995), Rev. 18:1.
 "The speaker [at Rev. 19:9] is one of the angels of the seven last plagues who initiated his role as John's guide in Rev. 17:1."—Ibid., Rev. 19:9.
 E. W. Bullinger, Commentary on Revelation (Grand Rapids, MI: Kregel Publications, 1984, 1935), Rev. 18:2.