What is the Mark of the Beast?

The common phrase, the "Mark of the Beast," seems to be ubiquitous when talking about the end of times. People have even gone to the lengths of saying that COVID-19 is the "Mark of the Beast," but it is not. Rather, it seems to be a precursor leading up to what will truly be the "Mark of the Beast." When the Antichrist comes to impersonate Christ and rule the world, he will make all