There is a theme in world religious history and in scripture of a place being so evil that morally it warrants urgent escape endeavours by the godly.
Sodom and Gomorrah were being destroyed by God for their extreme ungodliness, and Lot, a righteous man, was helped to escape by God just before the destruction fell.
Egypt was so hostile to the Hebrews it had enslaved that God sent Moses to help the Hebrews escape, in a series of terrible plagues that forced the Pharaoh to let them leave.
People of ancient Judah had to escape exile in Babylon. There were prophecies urging them to leave and return to Judah.
Isaiah 48:20 – "Leave Babylon, flee from the Babylonians! Announce this with shouts of joy and proclaim it. Send it out to the ends of the earth; say, ‘The Lord has redeemed his servant Jacob.’”
Isaiah 52:11-12 – "Depart, depart, go out from there! Touch no unclean thing! Come out from it and be pure, you who carry the articles of the Lord’s house. But you will not leave in haste or go in flight; for the Lord will go before you, the God of Israel will be your rear guard."
Jeremiah 29:10 – "When seventy years are completed for Babylon, I will come to you and fulfill my good promise to bring you back to this place."
Jeremiah 50:8 – "Flee out of Babylon, leave the land of the Babylonians, and be like the goats that lead the flock."
Jeremiah 51:6 – "Flee from Babylon! Run for your lives! Do not be destroyed because of her sins. It is time for the Lord’s vengeance; he will repay her what she deserves."
Centuries later, the apostle Peter’s is believed to have used "Babylon" as a coded reference to Rome:
1 Peter 5:13 – "She who is in Babylon, chosen together with you, sends you her greetings, and so does my son Mark."
The idea of leaving Babylon is applied to the Church in:
Revelation (Babylon the Great as the wicked Rome system to be avoided)
Revelation 18:4-5 – "Then I heard another voice from heaven say: 'Come out of her, my people,' so that you will not share in her sins, so that you will not receive any of her plagues; for her sins are piled up to heaven, and God has remembered her crimes.’"
Hebrews (Believers seeking a better, heavenly homeland)
Hebrews 11:13-16 – "All these people were still living by faith when they died. They did not receive the things promised; they only saw them and welcomed them from a distance, admitting that they were foreigners and strangers on earth. ... Instead, they were longing for a better country—a heavenly one."
Paul (Calling for separation from spiritual impurity)
2 Corinthians 6:17 (quoting Isaiah 52:11) – "Therefore, ‘Come out from them and be separate, says the Lord. Touch no unclean thing, and I will receive you.’"
The theme turns full circle in Revelation 11 where the city of Jerusalem is seen as a place to escape from, called prophetically Egypt and Sodom.
"And their dead bodies will lie in the street of the great city, which is called spiritually Sodom and Egypt, where also their Lord was crucified." (Revelation 11:8)
The theme is shown to be there in all scripture, that whatever the particular place, any place can become so evil that escaping from it is in the will of God as a matter of salvation, to escape association with its sins and therefore culpability warranting punishment from God.
Hebrews 13:12-14 – "Jesus also suffered outside the city gate to make the people holy through his own blood. Let us, then, go to him outside the camp, bearing the disgrace he bore. For here we do not have an enduring city, but we are looking for the city that is to come."
One day, perhaps years from now, it will become vitally important for the saintly believers to flee certain cities and their spheres of influence. Rome, and Jerusalem.