Revelation 13:15-17

He was then permitted to give life to this statue so that it could speak. Then the statue of the beast commanded that anyone refusing to worship it must die. He required everyone—small and great, rich and poor, free and slave—to be given a mark on the right hand or on the forehead. And no one could buy or sell anything without that mark, which was either the name of the beast or the number representing his name.