Albert Barnes Commentary Zechariah 14:3

"Then shall Jehovah go forth, and fight against those nations, as when he fought in the day of battle." — Zechariah 14:3 (ASV)

The Lord shall go forth and shall fight - Jerome: “This is to be understood like that in Habakkuk, ‘You went forth for the salvation of Your people, for salvation with Your Anointed’ (Habakkuk 3:13), and in Micah, ‘For behold, the Lord comes forth out of His place, and will come down and will tread upon the high places of the earth, and the mountains shall be melted under Him, and the valleys shall be cleft’ (Micah 1:3–4); and Isaiah also, ‘The Lord shall go forth as a mighty man; He shall stir up jealousy like a man of war; He shall cry; He shall prevail over His enemies’ (Isaiah 42:13).

“God is said to ‘go forth’ when by some wondrous deed He declares His Presence. His Deity is, as it were, held in reserve, as long as He restrains Himself and does not by any sign show His power. But He ‘goes forth,’ and bursts forth, when He exercises some judgment and works some new work which strikes terror.”

God then will “go forth out of His place” when He is compelled to break through His quietness, gentleness, and clemency for the correction of sinners. He who elsewhere speaks through the prophet, ‘I, the Lord, change not’ (Malachi 3:6), and to whom it is said, ‘Thou art the same’ (Psalms 102:28), and in the Epistle of James, ‘With whom is no change’ (James 1:17), now ‘goes forth’ and ‘fights as in the day of battle,’ when He overwhelmed Pharaoh in the Red Sea and ‘fought for Israel.’”

“The Lord shall fight for you” became the watchword of Moses (Exodus 14:14; Deuteronomy 1:30; Deuteronomy 13:22; Deuteronomy 20:4); of the warrior Joshua in his old age (Joshua 23:10; compare Joshua 10:14, Joshua 10:42; Joshua 23:3), after his life’s experience (Joshua 10:14, Joshua 10:42; Joshua 23:3); and of Nehemiah. “Be not afraid by reason of this great multitude” (Nehemiah 4:20), said Jahaziel, son of Zachariah, when the “Spirit of the Lord came upon” him; “for the battle is not yours, but God’s” (2 Chronicles 20:15).

As He fought in the day of battle - Osorius: “All wars are so arranged by the power of God, that every victory is to be attributed to His counsel and will. But this is not seen so clearly when people, elated and confident, try to claim for themselves all or the greater part of the glory of war. Then the war may be preeminently said to be the Lord’s, when no one drew sword, as it is written, “The Lord shall fight for you, and you shall hold your peace” (Exodus 14:14). Of all God’s wars, in which human insolence could claim no part of the glory, none was more wondrous than that in which Pharaoh and his army were sunk in the deep. “The Lord,” said Moses (Exodus 15:3), “is a man of war: the Lord is His Name.” That day of battle was the image of one much greater.

In the former, Pharaoh’s army was sunk in the deep; in the latter, the power of evil, in Hell; in the former, what could in some measure be conquered by human strength was subdued; in the latter, an unconquerable tyranny; in the former, a short-lived liberty was established; the liberty brought by Christ through subdual of the enemy is eternal. As, then, the image yields to the truth, earthly goods to heavenly, perishable things to eternal, so the glory of that ancient victory sinks to nothing compared to the greatness of the latter.”