Concise Bible Dictionary:
This is also called “MYSTERY,” “THE MOTHER OF THE HARLOTS AND OF THE ABOMINATIONS OF THE EARTH” (Rev. 17:5). Some great religious system is alluded to, with whom the kings of the earth had had illicit intercourse, and by whom the merchants of the earth had been made rich. It had also been guilty of shedding the blood of the saints and the blood of the martyrs of Jesus. It is compared to a woman arrayed in purple and scarlet, and decked with gold and precious stones and pearls, having a cup in her hand, full of abominations and filthiness of her fornication. Could there possibly be drawn a more vivid and life-like portrait of the worldly and idolatrous system of the apostate Church, whose center is at Rome, than is here drawn by the pen of the Holy Spirit? To make it doubly sure as to who is represented by the description it is added “The seven heads are seven mountains, on which the woman sitteth” (Rev. 17:9), “the seven-hilled city” being a well-known appellation of Rome.
It is further revealed that the ten horns (the ten kingdoms of the future Roman empire) will make war with the woman, make her desolate and naked, will eat her flesh and burn her with fire. Heaven, the apostles and prophets are called on to rejoice over the fall of that seductive and soul-destroying system: (Compare Rev. 14:8; Rev. 16:19; Rev. 17:1-18; Rev. 18:1-24; Rev. 19:1-3).
It should be noted that though Papal Rome is one of the worst of the antichrists, and the one that has had sway for the longest period; yet she is not what is called in scripture the Antichrist or Man of sin: she is rather the anti-church. He also is found in the Revelation as a beast, having two horns like a lamb, and speaking as a dragon; and also as the false prophet (Rev. 13:11; Rev. 20:10). See ANTICHRIST.