וַיְהִ֥י מִבְחַר־עֲמָקַ֖יִךְ מָ֣לְאוּ רָ֑כֶב וְהַפָּ֣רָשִׁ֔ים שֹׁ֖ת שָׁ֥תוּ הַשָּֽׁעְרָה׃
And it came to pass, when thy choicest valleys were full of chariots, And the horsemen set themselves in array at the gate,
Read kabbalistic (mystical) interpretation of Isaiah 22:7: and classical mystical sources.