Revelation 13:16-18

Rotherham(i) 16 And he causeth all—the small and the great, and the rich and the poor, and the free and the bond,—that they should give unto them a mark, upon their right hand or upon their forehead; 17 [and] that no one should be able to buy or to sell, save he that hath the mark, the name of the beast, or the number of his name. 18 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 666.