Revelation 13
15 Ref And it was given `unto him' to give breath to it, `even' to the image to the breast, that the image of the beast should both speak, and cause that as many as should not worship the image of the beast should be killed.
16 Ref And he causeth all, the small and the great, and the rich and the poor, and the free and the bond, that there be given them a mark on their right hand, or upon their forehead;
17 Ref and that no man should be able to buy or to sell, save he that hath the mark, `even' the name of the beast or the number of his name.
18 Ref Here is wisdom. He that hath understanding, let him count the number of the beast; for it is the number of a man: and his number is Six hundred and sixty and six.