Can you be Saved AFTER Receiving the Mark of the Beast? (John MacArthur says Yes)

There seems to be a renewed interest in the mark of the beast, even showing up in a recent podcast on Joe Rogan. And yes, Joe Rogan was actually reading from the book of revelation on his podcast just recently.
This reminded me of a controversy over John MacArthur’s comments that one can still be saved after receiving the mark of the beast… What do you think?