The ancient kingdom of Elam was once a formidable power, threatening massive empires like Babylon, Assyria, and Persia. In fact, the famous city of Shushan began as an Elamite capital before it was later absorbed by the Persians [ביאור שטיינזלץ]. Against this backdrop of historical dominance, a divine prophecy foretells the sudden collapse of Elam's military might.
At the heart of this downfall is God's declaration that He will break their bow. Commentators offer two ways to understand the significance of this weapon. Looking at the military reality of the ancient world, some explain the destruction quite literally. The warriors of Elam were famous for their archery, and their primary combat strength relied entirely on their skill with a bow [מצודת דוד, מלבי״ם, אברבנאל]. Conversely, others view the weapon as a broader metaphor. Just as a physical bow gives a soldier confidence and a tactical advantage in battle, it represents Elam's overall hope, resilience, and national power [רש״י, רד״ק].
Whether understood as a physical weapon or a symbol of national strength, the shattering of this bow represents a direct strike by God at the absolute peak of their power. The destruction is not aimed at the weaker edges of the empire, but rather at the choicest and most elite parts of their forces [רש״י, מצודת ציון, מלבי״ם]. Ultimately, God will wipe out the highest level of their military capability and destroy the very foundation of their strength.