What about those who have no knowledge of scriptures that are around when the mark of the beast becomes necessary for commerce?? It may be presented in a way that seems harmless, how will they be saved?
God is just. He can’t condemn someone who couldn’t have known what He requires of them. Right after the false prophet issues an order forcing everyone to receive the Mark of the Beast, God will send three angels to Earth. The first will proclaim the everlasting Gospel to every nation, tribe, language, and people. The second will announce that Babylon’s destruction is imminent, and the third will warn the people of Earth that anyone who decides to take the mark will suffer eternal punishment (Rev. 14:6-11).
In short there will be no one on Earth without the knowledge of the Gospel, no one who hasn’t been warned against taking the mark, and no possibility of salvation for those for those who take it anyway.