When a great empire collapses, the ruin extends far beyond its own citizens. The artificial bonds that hold a massive, cosmopolitan capital together instantly dissolve, triggering a sudden, panicked exodus of all the foreigners who had sought refuge, wealth, or military alliances within its walls. Stripped of these superficial ties, the masses are overtaken by the most basic survival instinct: the desperate drive to return to their roots.
The primary approach among commentators is that this chaotic flight involves the foreign population residing in Babylon, such as merchants, immigrants, and the foreign mercenaries drafted to defend the city. As the empire falls, these groups hastily abandon it. Alternatively, some perspectives suggest the panic grips the Chaldean masses—the Babylonians themselves [אבן עזרא]—or applies universally to every single inhabitant of the city [רש״י].
To capture the sheer terror of this escape, the scene is painted through two distinct animal metaphors. First is the image of a hunted deer, driven from its home and running frantically to escape hunters or predators [רש״י, רד״ק, מצודת דוד, אבן עזרא, אברבנאל], or wandering blindly in total confusion [שד״ל]. The second image is of sheep separated from their flock. Without a shepherd to gather and protect them, they are left entirely lost, vulnerable, and unable to find their way back [מצודת דוד, אברבנאל].
A careful distinction can be made between these two animals, reflecting the different ways people react when fleeing for their lives [מלבי״ם]. A deer is naturally a solitary creature, yet it relies on finding a specific, secure physical shelter in the rocks. This mirrors those who immediately run toward their geographical homeland, seeking the safety of their physical borders. Sheep, on the other hand, rely entirely on the safety of the herd. This represents those who first seek out their own people, desperate to band together and escape as a protected, unified group.
On a deeper level, the choice of these specific animals reflects a profound sense of divine justice, punishing the empire measure for measure [חומת אנך]. Babylon experiences the terror of a hunted deer because it waged war against the Land of Israel, which is known biblically as the Land of the Deer. Likewise, the empire is scattered like lost sheep because it ruthlessly attacked the people of Israel, who are the flock of God's pasture.