"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 . . . And they worshiped the dragon which gave power unto the Beast: and they worshiped the Beast, saying, Who is like unto the Beast? who is able to make war with him? . . . 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."
The Revelation of St. John the Divine

Let him that hath understanding enter here the true number of the Beast, and the same shall be made to enter in . . .