The removal of Satan is the first necessary step to set up the great test for men (in the millennial kingdom): to see if they can live a blameless life— without being tempted by Satan. The idea is that with Satan and his demons out of the picture, unregenerate man will have a fair chance to live without sin (even though they will be born in sin).

Thus, just before the beginning of the millennium (Rev. 20:2-3), Satan (along his demons) will be cast into a bottomless pit, to be held there for the entire duration of the millennium.

And also, at the beginning, all unregenerate (unsaved) people will be killed, either in the battle of Armageddon (Rev. 19:15-21) or in the judgment known as the sheep and goat’s judgment (Matt. 25:31-46). Therefore, from the beginning of the millennial kingdom, there will be no unsaved people. All who go…