In an earlier message (Ezekiel 31:17–18), God said that Egypt would go down to join other nations in the place of the dead. Here that idea is explained more fully.
Egypt would share the fate of those who were rejected and those killed by the sword. They would go to the Pit, a word that describes the place of the dead.
This place of judgment was already filled with many nations. These nations were once powerful, but they had fallen and been destroyed (compare Isaiah 14:9–11).