Come out of us because of our sins?
Satan is the “Snake” in Genesis, the most cunning of creatures. As events progress, the snake becomes Leviathan and Dragon to describe just how horrible and scary the Beast is. Leviathan swims the abyss (hell), and winged Dragon flies the other void, the skies. I think God also describes the devil as a massive crocodile in the book of Job.
“Harlot” or “Whore” is the seduction of sin. Ever notice how a stripper dancing on a pole? Her seduction slithers like a snake.
During the time of Revelation's writing, “Whore of Babylon” commonly referred to Rome as a city that seduces men's souls. Other cities and empires noted for its seduction and corruption are “Byzantine” and Sodom and Gomorrah.
Could New York City fit that classification? Maybe. But, it that's the case, there are many other cities on the globe that equally seduce souls into disobedience—Las Vegas, Bangkok, Moscow, Berlin, London, and every city with a red light to go with its financial district.
Satan has grown in size and power for all the souls hell has devoured—literally.
From Genesis, Satan is the fallen “snake” that must crawl on its belly eating “dirt”. Other unclean animals also root in the dirt (or worse): swine, shrimp, and other bottom feeders. Other demonic creatures share a venomous bite such as scorpions. God emphasizes mankind's nature as “dirt” when Adam is punished with death of the body. God warns Cain, the first generation from our original parents, that “sin is a demon lurking at the door: his urge is toward you, yet you can be his master.”
We are called upon to “master” all creatures, especially the fallen supernatural creatures—like GREED. That's why so many recovery programs demand the patient's labeling the problem (i.e. drunkard must start by admitting they are an alcoholic).
That's also why Catholics, in the Sacrament of Reconciliation (sometimes called “Confession”) have a duty of NAMING the sins to TAKE DOMINION over the fallen creature, the demon(s) who plagues our souls. We are naming the fallen creatures in the same manner that our first parents, Adam and Even, named the creatures in the Garden of Eden but failed to master “DISOBEDIENCE” (similar to pride). This is why the Sacrament of Reconciliation is much more powerful than the Rite of Exorcism..
Why are fallen spirits given the names of sin? Because demons are the fruit of the forbidden tree. Similarly, we'll know false prophets by the same forbidden fruit they offer us. Conversely, Jesus Christ is the Eucharistic Fruit of the Living Tree, Who hangs upon the Cross of our Salvation.
As for 18: 4, is it any coincidence the timing of this message and today's financial events?
http://www.cbc.ca/world/story/2008/09/13/pope-france.html
Pope condemns love of money, power
"Then I heard another voice from heaven say: "Depart from her, my people, so as not to take part in her sins and receive a share in her plagues,".(Revelations 18: 4)
At the end of Reconciliation, our act of contrition is to "avoid the near occassion of sin."