Read or listen The Book of Revelation, chapter 18 online (ESV, YouVersion)

Fallen Babylon 18:1-3

John sees an angel who shows him the destruction of Babylon. This has already been promised (Revelation 14:8) and now follows a detailed description of how the Devil’s kingdom will fall. The Devil’s kingdom is now as if founded on mountains. It seems unshakable. But one day it will be like a destroyed city. It lived a luxurious life, but its splendor did not last forever. A prosperous city can be destroyed to the ground. So will the Evil One’s kingdom.

Go out! 18:4-8

Before John hears the description of the destruction of Babylon, he hears God’s command to his people to leave the city before it is destroyed. What does this command mean? Jesus told his people to leave Jerusalem before it is destroyed (Matthew 24:15-20). Many Christians heeded Jesus' warning when they saw the destruction approaching, and escaped death when the Roman armies invaded Jerusalem in the fall of 70 AD. A similar warning is unlikely to be in question now. Babylon in the Book of Revelation does not refer to an ordinary city from which one could flee, but to the kingdom of the Devil.

Many have understood the commandment to mean that God's people must leave the evil world. Monasteries have been founded and it has been thought that in a monastery one can avoid the sins of the world and get rid of the Devil. This has not happened. Sin is real and the Devil also works in monasteries - even there, where sinful people live and dwell.

Others have understood the commandment to mean that God's own must separate from the secular church and establish congregations of true believers that do not have the problems of the secular church. This has been done, but despite good intentions, the attempt has not been successful. Sin has also penetrated these churches, for their members are also human. The devil has usually succeeded in breaking them up into smaller and smaller groups that quarrel among themselves.

If Babylon represents the kingdom of the Devil, the command to get out of it would mean to renounce the activities of the Devil's servants. For the first Christians, it meant, for example, not fraternizing with the beast that fought against the Church of Christ – the Roman Empire. Judgment awaits the kingdom of the Devil, and whoever is committed to that kingdom and its servants will also face judgment on the day when Babylon is destroyed. So we must see where the Devil and his servants are working to destroy the church of Christ, and stay separate from that work. That would be leaving Babylon.