Verse 4.
This strikingly represents the most pompous and costly manner in which the Latin Church has held forth to the nations the rites and ceremonies of its idolatrous and corrupt worship.
Verse 5.
This inscription being written upon her forehead is intended to show that she is not ashamed of her doctrines, but publicly professes and glories in them before the nations: she has indeed a whore's forehead, she has refused to be ashamed… This woman is also called Babylon the Great; she is the exact antitype of the ancient Babylon in her idolatry and cruelty, but the ancient city called Babylon is only a drawing of her in miniature. This is indeed Babylon THE GREAT. "She affects the style and title of …the CHURCH; but she is, in truth, the mother of harlots and abominations of the earth."
-Adam Clarke Commentary-
