יהושע, פרק ז׳, פסוק ו׳

The unexpected military defeat drives the leadership into a state of deep physical mourning and urgent pleading. Joshua responds first by tearing his clothes [ביאור שטיינזלץ], a direct expression of grief for the soldiers who lost their lives in the battle [מלבי״ם]. Following this, he falls on his face before the Ark of God, positioning himself in a posture of intense prayer [מלבי״ם].

Finally, Joshua and the elders place dust upon their heads. This action carries profound weight. It is a sign of mourning that stems not merely from the tactical loss of the battle, but from the troubling, deeper significance behind the defeat [ביאור שטיינזלץ]. Furthermore, covering themselves in dust demonstrates complete submission before God. It serves as a symbolic declaration by the leaders that they view themselves as nothing more than the dust of the earth [מלבי״ם].