In the Book of revelations there is a verse that speaks about the Mark of the Beast (traditionally 666) eventually being emblazoned on humans by Satan. Here's the verse:
"And he causeth all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads: And that no man might buy or sell, save he that had the mark, or the name of the beast, or th…