A vivid image of fire rapidly consuming straw illustrates the ultimate future conflict between Israel and the nations. In this picture, fire and its reaching flames represent the strength of Israel, while thin, easily burned straw represents Esau [מצודת ציון].
The power of Israel is presented through two distinct forces, the family of Jacob and the family of Joseph. The primary approach among commentators views this as poetic phrasing. They explain that the historically divided kingdom will reunite in the future, and the entire nation is often referred to by Joseph's name [רד״ק, אבן עזרא, מצודת דוד]. Other perspectives see a specific division of roles for the final apocalyptic battles. Jacob acts as a fire that consumes enemies from up close, while Joseph is a flame that reaches from afar. This distant flame represents the ten lost tribes returning from their distant exile in Assyria to join the conflict, or the military strength of a future messianic leader from the line of Joseph [מלבי״ם, אברבנאל].
On a deeper spiritual level, an ancient tradition dictates that Esau's descendants can only be defeated by the descendants of Rachel [רד״ק, אברבנאל]. Jacob embodies the merit of studying Torah, which acts as a spiritual fire. Joseph represents the power of self-sacrifice and the ability to overcome negative urges. Together, this spiritual blaze is destined to banish the power of Esau, who is compared to a snake rooted in the dust [צוארי שלל, חומת אנך].
The comparison of Esau to straw carries a specific meaning regarding the timing of his downfall. Throughout the long exile, Esau absorbed and trapped many sparks of holiness. As long as these holy fragments remain within his domain, he is protected from absolute destruction. However, in the future, the Divine Presence will extract all these holy elements. Left entirely empty and lifeless, Esau will finally become like dry straw, completely vulnerable to the fire [צוארי שלל, חומת אנך].
When the burning begins, it will target either the Edomites, historically associated with the Roman and Christian empires [אברבנאל, ביאור שטיינזלץ], or the Chaldeans [מצודת דוד]. This destruction will also be internal. Just as pieces of burning straw ignite one another, Esau's forces will turn on each other and destroy themselves in battle [מלבי״ם]. The outcome will be absolute, leaving not a single survivor from Esau's lineage [אברבנאל, צאינה וראינה]. The certainty of this event is guaranteed because God Himself has spoken it [מצודת דוד, צאינה וראינה]. This divine promise traces back to an earlier prophecy in the Book of Numbers, where Balaam foretold that a ruler emerging from Jacob would ultimately destroy all remaining enemies [רש״י].