What is the purpose of sealing Satan in the bottomless pit?
The sealing confines Satan in the bottomless pit for the thousand-year period so he can deceive the nations no more. It prevents his deception during the millennial kingdom, because he is not yet sent to the eternal Lake of Fire; afterward he must be loosed for a little season to test the nations.
Les explains that the bottomless pit is a unique place known only to God where Satan is confined for the thousand-year period. God does not send Satan to the Lake of Fire yet because that is a place of eternity, and Satan is not ready for eternity; he has one more opportunity at the end of the thousand years. The seal ensures Satan will deceive the nations no more until the thousand years are fulfilled. After that he must be loosed for a little season, because the millennium becomes another period of testing—the seventh, after six previous periods of testing in human history—so new generations in the kingdom economy can be tested.