כְּק֣וֹל מַרְכָּב֗וֹת עַל־רָאשֵׁ֤י הֶֽהָרִים֙ יְרַקֵּד֔וּן כְּקוֹל֙ לַ֣הַב אֵ֔שׁ אֹכְלָ֖ה קָ֑שׁ כְּעַ֣ם עָצ֔וּם עֱר֖וּךְ מִלְחָמָֽה׃
Like the noise of chariots, On the tops of the mountains do they leap, Like the noise of a flame of fire That devoureth the stubble, As a mighty people set in battle array.
Read midrashic interpretation of Joel 2:5: and classical rabbinic exegesis.