16 And he forces all persons, the great and the small, rich and poor, free and slave, to receive a mark in their right hand, or in their foreheads.17 No one could buy or sell without the mark, the name of the beast, or the number of its name.18 This requires wisdom. Let him that has understanding calculate the number of the beast: for it is the number of a man; and his number is six hundred and sixty-six.