ירמיהו, פרק נ״א, פסוק ל׳

The fall of Babylon is marked by a complete moral and physical collapse of its once-mighty military force. Faced with an invading army, the Babylonian warriors are overcome by fear. Instead of marching out to the battlefield, they simply stop fighting. They retreat and lock themselves inside fortified strongholds and secure towers, hoping only to protect themselves.

Their legendary bravery completely vanishes. Commentators agree that their courage simply departs from them. [רש"י] adds that the nature of this loss implies a sudden shifting or moving away from place to place, much like a displaced nerve. Their power literally abandons them, leaving them weak and completely helpless.

While the soldiers hide, the city's defenses fail. The heavy bars designed to lock the city gates are broken, leaving Babylon wide open to the invasion. Soon, the residential homes are set on fire. Because it is not explicitly clear who starts the fires, two distinct possibilities emerge. The primary approach among commentators is that the invading enemies burn the houses as they sweep through the city. However, [מלבי"ם] offers a different perspective, suggesting that the Babylonian warriors themselves set their own buildings on fire. In this view, the burning is a desperate tactical move designed to prevent the invading forces from finding shelter and housing within the city walls.