What is the bottomless pit?
The bottomless pit is a unique place known only to God where Satan will be confined for the thousand-year period. It is not the Lake of Fire, which is eternal; Satan will be locked there, shut up and sealed, unable to deceive the nations until the thousand years are fulfilled, after which he must be released for a little season.
Les teaches that the bottomless pit is a unique place known only to God, not the Lake of Fire, because the Lake of Fire is a place of eternity and Satan is not ready for eternity yet. Satan is cast into the bottomless pit, shut up, and sealed so he should deceive the nations no more until the thousand years are fulfilled. After that, he has to be loosed for a little season. The millennium then becomes another period of testing—the seventh period of testing the human race, since God always does things in seven. Satan will be released to test the new generations that come on the scene in that kingdom economy.