Revelation 13:16-18 And he causes everyone, both small and great, rich and poor, free and slave, to receive a mark on his right hand, or on his forehead:

VIN⁽ⁱ⁾ ¹⁶ And he causes everyone, both small and great, rich and poor, free and slave, to receive a mark on his right hand, or on his forehead: ¹⁷ so that no one can buy or sell unless he has the mark, which is the name of the beast or the number of his name. ¹⁸ Here is wisdom: He who has understanding, let him calculate the number of the beast, for it is a number of a man. And its number is 666