A divine promise of unprecedented military support guarantees the removal of all physical and strategic barriers standing in the way of a conqueror. God pledges to pave the path forward and breach even the most impenetrable fortresses, ensuring no force can withstand the advance. The primary approach among commentators is that God marching ahead serves as a metaphor for divine assistance that secures victory in battle, as though God Himself is leading the front lines [רד״ק, מצודת דוד, אבן עזרא]. Another perspective suggests this forward movement hints at the guidance of the specific angel appointed over the Persian empire [אבן עזרא]. Such profound intervention is necessary because the natural strength of the conqueror is simply too weak to achieve this level of military success on its own [מלבי״ם].
As the army advances, it encounters various obstacles that require divine intervention. The primary approach among commentators is that these barriers are winding, twisted, or broken roads that curve sharply in different directions [רש״י, רד״ק, שד״ל, מצודת ציון]. Others view these obstacles as physical terrain challenges, such as mountains and uneven ground [אבן עזרא, ביאור שטיינזלץ], or even the massive walls surrounding a fortified city [רש״י]. God promises to level and straighten these hazards so the advancing soldiers will not stumble [מצודת דוד]. From a strategic standpoint, roads leading to ancient fortresses were intentionally built with sharp curves to prevent a direct, high-speed assault on the main gates. God pledges to eliminate these defensive curves, allowing for a swift and unimpeded approach [מלבי״ם].
The final stage of the conquest involves the total destruction of the city defenses, specifically the heavy copper gates of the nations [אבן עזרא] and the massive iron bars placed behind them to keep them locked [מצודת ציון]. The primary approach among commentators is that the shattering of these materials is a metaphor for the complete collapse of the strongest, most secure fortresses [מצודת דוד, רד״ק]. However, this destruction also contains a truly miraculous element. In a standard siege, attackers must first break the internal iron bars locking the gate before the doors can be opened. God promises to upend this natural order entirely: He will first shatter the massive doors themselves, and only then cut down the iron bars within [מלבי״ם].