Revelation 17:9

"And here is the mind which hath wisdom. The seven heads are seven mountains, on which the woman sitteth."

Cross References (ranked by relevance)

Revelation 13:18

Here is wisdom. Let him that hath understanding count the number of the beast: for it is the number of a man; and his number is Six hundred threescore and six.

Revelation 17:7

And the angel said unto me, Wherefore didst thou marvel? I will tell thee the mystery of the woman, and of the beast that carrieth her, which hath the seven heads and ten horns.

Matthew 13:11

He answered and said unto them, Because it is given unto you to know the mysteries of the kingdom of heaven, but to them it is not given.

Revelation 17:18

And the woman which thou sawest is that great city, which reigneth over the kings of the earth.

Revelation 17:3

So he carried me away in the spirit into the wilderness: and I saw a woman sit upon a scarlet coloured beast, full of names of blasphemy, having seven heads and ten horns.

Hosea 14:9

Who is wise, and he shall understand these things? prudent, and he shall know them? for the ways of the LORD are right, and the just shall walk in them: but the transgressors shall fall therein.

Matthew 24:15

When ye therefore shall see the abomination of desolation, spoken of by Daniel the prophet, stand in the holy place, (whoso readeth, let him understand:)

Daniel 12:4

But thou, O Daniel, shut up the words, and seal the book, even to the time of the end: many shall run to and fro, and knowledge shall be increased.

Revelation 13:1

And I stood upon the sand of the sea, and saw a beast rise up out of the sea, having seven heads and ten horns, and upon his horns ten crowns, and upon his heads the name of blasphemy.