Well, just to let you who dont know, it originated from the bible

"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 the number of his name. Here is wisdom. Let him that hath understanding count the number of the beast: for it is the number of a man; and his number is Six hundred threescore and six" (Revelation 13:16-18).
So it will apear on every person who is under satans influance, on their forehead or their hands and they will be cast into the lake of fire The others (people of God) will be allowed into heaven.