The article states, "In order to fully appreciate Sunday as a mark of Christian unity we must expand our definition of unity." And the Bible says, "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" (Revelation 13:16-17).