וְיָצָ֣א יְהוָ֔ה וְנִלְחַ֖ם בַּגּוֹיִ֣ם הָהֵ֑ם כְּי֥וֹם הִֽלָּחֲמ֖ו בְּי֥וֹם קְרָֽב׃
Then shall the LORD go forth, And fight against those nations, As when He fighteth in the day of battle.
Read kabbalistic (mystical) interpretation of Zechariah 14:3: and classical mystical sources.