And he causes all, the small and the great, and the rich and the poor, and the free men and the slaves, to be given a mark on their right hand, or on their forehead,
and he provides that no one has the mark, either the name of the beast or the number of his name.
Here is the wisdom. Let him who has understanding calculate the number of the beast, for the number is that of a man; and his number is six hundred and sixty-six.
Revelation 13:16-18