Charles Ellicott Commentary Revelation 17:9

"Here is the mind that hath wisdom. The seven heads are seven mountains, on which the woman sitteth:" — Revelation 17:9 (ASV)

And here is the mind . . . — It is better to read, Here (omit “and”) is the mind, etc. Attention is called to the fuller explanation that follows. It requires true wisdom to observe many incidents of the world’s history and not find stumbling-blocks in them (Psalms 73:2–3; Psalms 119:165).

The seven heads are seven mountains where the woman sits upon them. The description seems to be drawn from Rome, the seven-hilled city. This keeps the reference to Rome before us, yet at the same time, the further explanation (Revelation 17:10) broadens our thoughts and shows us that the literalism on which the imagery is based is used to convey a wider symbolic meaning.

The seven heads are seven mountains, etc., and they (the seven heads; the words “There are seven kings” in the English version are confusing) are seven kings: the woman rides on the seven-headed beast; just as Rome dwells on her seven hills, so also the world-city, seen in vision, sits among the various empires that have risen, like great mountains, in the history of the world.