The prophet challenges the Moabites with a sharp rhetorical question, targeting their deep military pride and the way they view themselves. For a nation that boasts of its strength, the prophet mocks their sudden helplessness, asking where their bravery is hiding now that destruction has arrived [ביאור שטיינזלץ, מצודת דוד].
To fully understand the arrogance of the Moabites, one must look at how they classify their forces. They pride themselves on possessing two distinct types of power. First, they claim to have men born with raw, natural physical strength. Second, they boast of their professional soldiers, warriors who have spent years mastering military tactics and combat skills [מלבי״ם].
However, their crushing defeat exposes these claims as completely empty. In a typical battle, the bravest soldiers rush up to the city walls to fight the enemy, while the vulnerable civilians retreat downward to hide. Yet, during the fall of Moab, the exact opposite happens. The ordinary citizens are the ones who flee to the high places, only to be killed there. Meanwhile, the supposedly elite, trained warriors do not step up to fight at all; instead, they go down to their own slaughter. This complete reversal of normal warfare is the ultimate proof that they do not deserve to be called men of war [מלבי״ם].