The mark of the beast is not keeping God's commandments. Loving the things he finds abominable. Those things are not forced on us. We either accept them, or we don't. God will know.
I think the mark of God is His Spirit. The mark of the beast may be a demonic spirit.
When early Christians paid their taxes, they had to swear allegiance to Caesar and say “Caeser is Lord”, and they couldn’t say that so they were killed. In taking the mark, people will most liely have to swear that the antichrist is Lord (god), and they will be beheaded.