"As we have already shown there are two cities and two women presented in the book of Revelation. One of the cities is the holy city, New Jerusalem. The other is called Mystery Babylon. They are symbols and symbols are not what they are called, therefore neither of the two cities is a literal city somewhere on earth. If they are not cities, what are they? They are symbols of something else. If they were real cities, as many commentators suppose, they would not be among all the beautiful symbols of the book of Revelation, which is entirely a book of symbols. Most of the preachers today have the first city confused with other things. The vast majority think that New Jerusalem is a description of heaven; therefore they talk about the city as heaven, having golden streets and mansions over the hill-top. But New Jerusalem cannot be heaven because John sees it coming down from God out of heaven! Church theology today has the Holy City, Heaven, and the Kingdom of God all mixed up and confused. Confused -- oh, yes, that is the mark of Babylon! It is obvious they do not know what the New Jerusalem is, nor what Heaven is, nor what the Kingdom of God is!"
Much more in the link:
"SPIRITUAL THINGS are real, they do exist, but they are not natural, carnal, or earthly. If you don't understand the spiritual language, the symbol has no meaning."
"In the symbolism of prophecy a "city" signifies a religious government backed by power and influence."