What is "Shif'as Susav"?
Rashi: When there are many horses, they raise dust with their feet. It makes like a cloud, and darkens the land. This is like "v'Shif'as Mayim 1 Techaseka" (Iyov 22:11).
Radak: This is multitude, like "Shif'as Gemalim Techasech" (Yeshayah 60:6). It is an exaggeration to say that they will cover you.
Perhaps Rashi explains that this is a fog.
What is "Avakam"?
Radak: The dust that their feet kick up. Malbim ? this will suffice to cover you.
Will the noise make your walls shake?
Radak: This is an exaggeration. Malbim ? due to fear of his multitudes, it is as if the walls and towers will fall due to the noise alone.
What is the comparison "k'Mevo'ei Ir Mevuka'ah"?
Rashi citing Targum Yonasan: Like they enter a city that its wall was breached. Radak ? one enters without exertion or war. So they will enter your gates.
