Revelation 13:15-17

15And it was given to it to give breath to the image of the beast, that the image of the beast should also speak, and should cause that as many as should not do homage to the image of the beast should be killed.

16And it causes all, the small and the great, and the rich and the poor, and the free and the bondmen, that they should give them a mark upon their right hand or upon their forehead;

17and that no one should be able to buy or sell save he that had the mark, the name of the beast, or the number of its name.