Both Babylon and Satan will fall from their desires. Rather than be lifted up on high, they will be brought down.
Literary: Isaiah's image of the pit is the reversal of the "mount of the congregation" in verse 13. This is a reversal of location, symbolizing in the high and low the change in status. Babylon and Satan are in a pit because they do not just return to the ground level with the rest of the world, but just as their unrighteous aspirations were to lift themselves above, they have fallen below. Their penalty matches their prideful attempt to usurp the rightful place of God.