מִשִּׁפְעַ֥ת סוּסָ֖יו יְכַסֵּ֣ךְ אֲבָקָ֑ם מִקּוֹל֩ פָּרַ֨שׁ וְגַלְגַּ֜ל וָרֶ֗כֶב תִּרְעַ֙שְׁנָה֙ חֽוֹמוֹתַ֔יִךְ בְּבֹאוֹ֙ בִּשְׁעָרַ֔יִךְ כִּמְבוֹאֵ֖י עִ֥יר מְבֻקָּעָֽה׃
因他的馬匹眾多，牠們揚起的塵土必遮蓋你；騎兵、車輪和戰車的響聲必使你的城牆震動；他進入你的城門，必如同人進入已被攻破的城一般。
Rashi
From the abundance of his horses When there are many horses, they raise dust with their feet, which ascends and becomes like a cloud, darkening the earth. This is called שִּׁפְּעַת, an abundance. Similarly, (Job 22:11): “or an abundance of (וְשִּׁפְּעַת) water covers you,” de la foison in French, of abundance.
Rashi
as men enter a breached city as they enter a city that has been breached of its wall(Targum), that its wall has been breached.