A dramatic reversal transforms a once-bustling capital into a desolate wasteland. The sharp contrast between a glorious past and a ruined present stands at the heart of this prophecy of doom. The grand palace of the king of Judah is completely abandoned as the monarch is taken into exile [רש״י, מצודת דוד, אבן עזרא]. At the same time, the masses of ordinary citizens are driven from their homes, leaving the once-crowded urban streets entirely empty and forsaken [מצודת ציון, שטיינזלץ].
As the city falls, its mighty defenses collapse. The towering fortresses, high mounds, and strong watchtowers are brought to ruin [רד״ק, אבן עזרא, שטיינזלץ]. Taking a different approach, [רש״י] understands these fallen strongholds as a reference to the Temple, which had served as the ultimate spiritual and physical shield for the people. Once these great structures fall, their remains take on a new purpose. The primary approach among commentators is that the ruined towers will actually become caves for wild animals [רד״ק, מצודות, שטיינזלץ]. Adding a poetic perspective, [שד״ל] suggests that the hollow, empty towers simply look like caves from a distance. However, [רש״י] views this differently, explaining that the fortresses will simply be reduced to total rubble. Offering a completely original view, [מלבי״ם] explains that a great exchange takes place: wild animals and flocks will leave their actual caves and proudly take over the prestigious, ruined fortresses instead, rejoicing in their new homes.
The duration of this devastating ruin is said to last forever. [רש״י] understands this literally, meaning the desolation will remain until the end of days. Other commentators soften this, explaining that it simply refers to a very long time rather than true eternity [מצודת דוד]. Noting that historically the destruction only lasted a year or two, [שד״ל] offers alternative ideas: the ruins will resemble ancient caves that have existed since the beginning of time, or, quoting his son, the caves actually refer to graves, which are traditionally known as a person's eternal home.
Ultimately, the fallen city becomes a playground for nature. Wild donkeys, normally confined to the harsh desert, will happily roam the ruins, finding abundant pasture for their flocks [רד״ק, מצודות]. Taking this natural scene into the national and symbolic realm, [רש״י] explains that the wild donkeys represent the desires of the nation of Ishmael, while the grazing flocks symbolize the nation of Edom and its armies, who will feast upon the ruins of the defeated city.