8 And [kai] there followed [akoloutheo] another [allos] angel, [aggelos] saying, [lego] Babylon [Babulon] is fallen, [pipto] is
fallen, [pipto] that great [megas] city, [polis] because [hoti] she made [potizo] all [pas] nations [ethnos] drink [potizo] of [ek] the wine [oinos] of the wrath [thumos] of
her [autos] fornication. [porneia] KJV-Interlinear
another angel, a second one, followed, saying, "Fallen, fallen is Babylon
the great, she who has made all the nations drink of the wine of the passion of
her immorality." NASB
The first angel brought good news of salvation and eternity, and now the second angel brings bad news of failure and judgment.
Babylon is a reference to the anti-christs' worldwide empire. The anti-christ will demand that everyone worship him, or be executed. And, he will have control over the worlds political, military, economic, and religious power.
For our convenience the angel uses the term Babylon, because that is the history of Satan's evil attempts at destroying humanity. In the Tribulation, the actual terminology of the anti-christ (name, position, etc., which we do not now know) will be used rather than expressions of symbolism.
In either case, the population of the world will know and understand exactly who the angel is talking about.
From its inception, Babylon has symbolized evil which is accompanied with rebellion against God, Christ, and truth.
It was founded by Nimrod, Gen. 10:9. Likewise, Babel was the site of the first organized effort in idolatry and religion. Gen. 11:1-4. God destroyed the tower, confused the languages, and scattered the population to the four corners of the world, Gen. 11:5-9.
In the final days, the religions of the world will gather together and unite once again, into one ultimate and evil religion, under the anti-christ, and there God will destroy it finally and forever, Rev. 17:1-5.
And so the warning. The anti-christ has lost, so do not follow a loser. His loss is permanent and will last forever in the Lake of Fire. So do not follow a loser.
The anti-christ has been, and is, the cause of all the nations falling under the 'wrath and passion of immorality.'
The key word here is 'thumos,' which is a reference to strong and consuming lusts. The world will be engaging in extreme sins of passion and lust, and while this carries a connotation of deviant and perverse sexual activities, the real crime here is the prostitution of the spiritual life, in favor of the extremes of degenerate carnal behavior.
Of the many passages that describe the social morals, norms and standards of those last days, this word in this verse probably is the best description of them all. The fixation on sin will be so great, that even angels in the sky, teaching and preaching, will not be considered somewhat unusual, and therefore ignored.