Adam Clarke on Revelation 17:1

And there came one of the seven angels which had the seven vials, and talked with me, saying unto me, Come hither; I will show unto thee the judgment of the great whore that sitteth upon many waters - That idolatrous worship is frequently represented in Scripture under the character of a whore or whoredom, is evident from numerous passages which it is unnecessary to quote. See 1Chr 5:25; Ezekiel 16:1-63; 23:1-49, etc. The woman mentioned here is called a great whore, to denote her excessive depravity, and the artful nature of her idolatry. She is also represented as sitting upon many waters, to show the vast extent of her influence. See on Rev 17:13 (note).