שופטים, פרק ה׳, פסוק כ׳

The victory over Sisera's army was not a triumph of human military might, but a massive event where God harnessed the forces of nature and the universe to fight for the Israelites. The success on the battlefield was so absolute that it seemed as though the heavens themselves broke away from their regular routines to join the fray. Rather than winning by the sword, the Israelites witnessed God delivering a total victory [רלב״ג, רד״ק, מצודת דוד, ביאור שטיינזלץ]. Leaving their fixed orbits and natural paths [מצודת ציון, ביאור שטיינזלץ], these heavenly armies descended to fight the enemy without asking for any reward [רש״י].

Beyond the conceptual idea of heavenly assistance, the involvement of the stars had a very real and physical impact on the battlefield. The stars radiated an intense heat that boiled the iron armor worn by Sisera's soldiers. Desperate for relief from the burning metal, the troops rushed into the waters of the Kishon River to cool down. Once they were in the water, the powerful current swept them away and they drowned [מצודת דוד, רד״ק]. Another tradition pictures a star acting like a massive door bolt, anchored in the sky with its lower end reaching all the way down to the earth, striking a devastating blow directly against Sisera's camp [רש״י].

This celestial intervention was not a new phenomenon. The very same stars that had previously come to the aid of the Israelites during the wars of Joshua traveled along that familiar, well-worn path to fight against Sisera. A striking historical balance was created: just as Sisera called upon flesh-and-blood kings from ancient times to support his campaign, ancient heavenly forces from the dawn of history arrived to defend the Israelites [מלבי״ם].

The heavenly battle was perfectly mirrored on the ground. Much like the downfall of the Egyptians at the Red Sea, Sisera's formidable chariots became hopelessly tangled and sank in the river, while the Israelites crossed the very same waters safely and bravely without a single injury [רד״ק]. Because of these overwhelming miracles, it becomes clear that the Israelites never actually needed the military support of the tribes who chose to stay home. The deep anger directed at those absent tribes was not born out of a desperate need for more soldiers or operational support, but rather from the painful realization that they had abandoned basic brotherhood and common decency [אלשיך].