Overview
Babylon’s merchants are not literal merchants. Revelation uses buying and selling as symbols. Selling means offering salvation, and buying means accepting salvation. Therefore, wealth symbolizes being right with God.
Revelation describes her merchants as an integral part of Babylon. For example, they are ‘her’ merchants and become rich from her sensuality. Since Babylon symbolizes false religion, her merchants are the people who proclaim her false teachings.
Babylon’s sensuality, which is the source of the wealth of these false teachers, is the power of religion over people, which gives false teachers many followers.
Four Categories of People
Revelation describes Babylon as a woman with different relationships with different categories of people:

Kings – She sits on the Beast (Rev 17:3), meaning she “reigns over the kings of the earth” (Rev 17:18; cf. 17:9, 10). In return, the kings commit “acts of immorality” with her (Rev 17:2). They have a symbiotic relationship.
People of the world – The “many waters” on which she sits (Rev 17:1) symbolize the people of the world (Rev 17:15). Sitting on them means that “those who dwell on the earth were made drunk with the wine of her immorality” (Rev 17:2).
God’s people – She kills God’s people. “In her was found the blood of prophets and of saints and of all who have been slain on the earth” (Rev 18:24). In the Old Testament, literal Babylon was the main enemy of God’s people. For that reason, Revelation uses Babylon as a symbol for the great enemy of God’s Christian people.
Merchants – Since Babylon sits on the kings and the peoples (Rev 17:3, 15), she is distinct from the kings and the people. In contrast, the merchants are described as “your merchants” (Rev 18:23), meaning they are part of her and they work for her. This article discusses who Babylon’s merchants are.
Prophets of False Religion
Not literal wealth
The merchants “have become rich by the wealth of her sensuality” (Rev 18:3). This does not refer to literal wealth because the merchants are “the great men” (Rev 18:23) and because Revelation distinguishes between “great men” and “the rich” (Rev 6:15). Therefore, the merchants are not the literal wealthy people of the world.
False Prophets
For the following reasons, it is proposed that the merchants are the prophets and teachers of false religion:
(1) Buying and selling relate to salvation.
They are symbolic merchants because, in Revelation, buying and selling must be interpreted symbolically. Selling symbolizes offering salvation, and buying symbolizes accepting salvation. For example:
Jesus is also a Merchant. He sells refined gold and white garments to people (Rev 3:18), but He really offers salvation. To buy His gold and white clothes means to accept salvation. Show More
Jesus “purchased” people with His blood, meaning He saved them (Rev 5:9). Show More
Therefore, the merchants offer false assurance of salvation. In the end-time, when “no one will be able to buy or to sell, except the one who has the mark” (Rev 13:15), this means that nobody will be allowed to preach, except the people who have the Mark of the Beast.
(2) Being wealthy means being right with God.
As confirmation that the “merchants” trade false assurances of salvation, the letters to the seven churches use poverty and wealth as symbols of spiritual condition. Being wealthy symbolizes being right with God, and to be poor means to be lost. For example:
Jesus said to Smyrna: “I know … your poverty (but you are rich)” (Rev 2:9). In other words, Smyrna is poor in terms of worldly goods, but spiritually rich. They are right with God.
Laodicea is the opposite. To this church, Jesus said: “You say, ‘I am rich … and you do not know that you are wretched and miserable and poor and blind and naked” (Rev 3:17). When Laodiceans claim that they are rich, it means that they think of themselves as justified (right with God). When Jesus accuses them of poverty, it means they are far from God.
(3) The Merchants are part of False Religion.
A previous article identified Babylon as false Christianity (see here). Since the merchants are Babylon’s merchants (Rev 18:23), they work for her and are part of her. The statement that the merchants become great through Babylon’s deception implies that the merchants are integral to her:
“Your merchants were the great men of the earth, because all the nations were deceived by your sorcery” (Rev 18:23).
The devil and the false prophet deceive (Rev 12:9; 20:3, 8, 10; 13:14; 19:20). Since the merchants become great through deception, they are not independent, like the literally wealthy people of this world, but have become rich from false Christianity (Rev 18:15).
They sell a false assurance of salvation. Since all false teachings present a false picture of God’s character, they ultimately misrepresent Him. God so loved the world that He gave His only begotten Son (John 3:16). This wonderful truth is distorted, and we are told that God is cruel and judgmental.
Babylon’s sensuality
Continuing the symbolism of an immoral sexual relationship (Rev 17:2), Revelation 18:3 says that “the merchants of the earth have become rich by the wealth of her sensuality.”
What is “her sensuality?” Since Babylon is “the great harlot … with whom the kings of the earth committed acts of immorality” (Rev 17:1-2), “her sensuality” is what attracts the kings.
It does not ‘the sensuality of her wealth’ but “the wealth of her sensuality.” In other words, it is not her literal wealth that attracts kings.
Since Babylon symbolizes false religion, her sensuality is the power that religion has over people. “Kings” (political rulers) desire that power to strengthen their control over people.
“The merchants of the earth have become rich by the wealth of her sensuality” (Rev 18:3). The success of literal merchants is measured by their literal wealth. But these are symbolic merchants; symbols of Babylon’s false teachers. Their success is measured by how many followers they have. Babylon’s “sensuality” (the power of religion over people) assures them of many followers.
After Babylon and her sensuality have been destroyed, the merchants “mourn over her, because no one buys their cargoes any more” (Rev 18:11, 15). In other words, once Babylon’s sensuality had been destroyed, people would no longer accept the merchant’s false teachings.
Articles on Babylon
For general discussions of theology, I recommend Graham Maxwell, who you will find on the Pineknoll website.