Hi Marilyn,
The great harlot is one of the harlots of Mystery, Babylon the Great, the mystical kingdom of Satan and his angels.
The great harlot in Revelation 17 is the Vatican. But the Vatican, nor the RCC, are Mystery, Babylon the Great.
Mystery, Babylon the Great is not only the mother of prostitutes - all false religions - but also is responsible for the abominations of the earth.
____________________________________________________________________________________
The over-riding conflict in the Bible is the rebellion of Satan against God - that began when iniquity was found in Satan, which resulted in him to trying to upsurp God's creation and turn it away from worshiping God to worshiping himself, Satan.
The Scarlet beast is Satan. The mystery about Satan in verse 8 - when solved, is about how Satan used the garden of Eden serpent beast to upsurp God's creation, and that Satan will use the end time person - as the beast - for his agenda to rise above God and be worshiped like the Most High.
In verse 8 - the beast who was and is not - is the garden of Eden serpent beast.
the beast who was, is not, yet is - is the end times beast person.
_____________________________________________________________________________________
When we read about any conflict in the bible, at the root of it is the Satan against God conflict, that goes back to the beginning. Keep that in mind, and then what we read in Revelation will become clear.
Ezekiel 28:16 By the multitude of thy merchandise they have filled the midst of thee with violence, and thou hast sinned: therefore I will cast thee as profane out of the mountain of God: and I will destroy thee, O covering cherub, from the midst of the stones of fire.