A vivid metaphor presents God as a mighty warrior arming Himself for battle [אבן עזרא, שד״ל, מצודת דוד]. As He prepares for combat, His military attire is divided into two distinct categories, each serving a specific purpose. One set of gear is designed for the defense and salvation of the Israelites, while the other is meant for attack and vengeance against the nations of the world [רד״ק].
For defense, God equips Himself with the iron armor of righteousness, designed to deflect enemy swords and spears [מצודת ציון]. This righteousness does not stem from human merit; because the Israelites lack sufficient good deeds, God acts out of His supreme kindness to shield them from the strict demands of justice [מלבי״ם]. On a deeper level, just as a suit of armor is forged from many small metal scales joined together, every single coin a person gives to charity combines to create a massive protective shield [חומת אנך]. Along with the armor, He wears a copper warrior's helmet of salvation [מצודת דוד, שטיינזלץ]. The helmet, resting on the head, symbolizes God's ancient, hidden thought to bring salvation to the world [מלבי״ם]. Notably, armor and helmets are only worn during active combat, indicating that this period of war and defense for the Israelites is a temporary, passing phase [רד״ק].
Shifting to the offensive, God dresses in the splendid garments of vengeance to punish the nations that harmed the Israelites [מצודת דוד, מלבי״ם, רד״ק, מצודת ציון, אבן עזרא]. Unlike the temporary armor, these are regular clothes worn constantly, hinting that the subjugation of the nations as a consequence of the exile will be a permanent state [רד״ק]. Finally, He wraps Himself in an outer cloak of zeal [מצודת ציון, אבן עזרא, מלבי״ם]. This zeal represents God's jealousy for the honor of His great name, which was disgraced among the nations [רש״י]. Just as an outer cloak covers all other clothing and is easily seen by everyone, God's zeal and the restoration of His honor will be enacted publicly, in full view of all the world [מלבי״ם].