Why does it discuss the clamor of the nations?
Malbim: Now it discusses Machaneh Ashur. Do you clamor? Hashem will reprimand you "mi'Kolos Mayim Adirim"!
Who reprimanded whom?
Rashi: Hashem reprimanded the clamor.
Radak: Ga'arah applies also to water - "va'Yig'ar b'Yam Suf va'Yecherav" (Tehilim 106:9). Refer to 17:13:3:1.
Malbim: Refer to 17:13:1:1.
Why does it say "v'Nas mi'Merchak"?
Radak: In the Mashal, this refers to water - "ha'Yam Ra'ah va'Yanas", "Mah Lecha Ki Sanus" (Tehilim 114:3, 5). Hashem reprimanded Ashur's camp; He killed many, and the rest fled. It should say l'Merchak; mi'Merchak teaches that he fled from Yerushalayim, and even when he was far away, he fled far away, for he did not trust in himself - "v'Sal'o mi'Magur Ya'avor" (below 31:9).
Malbim: Hashem will rebuke him from His Kadosh Shamayim, and he will flee to Ninveh.
Who chased whom?
Radak: Sancheriv fled as if he was chased; Hashem's angel chased him.
Malbim: Hashem's rebuke chases Sancheriv.
What is "k'Motz Harim"?
Rashi: The Resha'im are compared to the worst species, and to the worst in that species - mountain chaff is drier than that of valleys.
Radak: The wind blows in mountains more than in plains. This teaches that his pursuer was strong.
What is "Galgal"?
Rashi: It is the blooming of thistles. At the end of summer, the wind flutters them, like a wheel with an axle in the middle and five arms around it. Malbim - the wind blows thorns more than chaff. Only the wind blows chaff, but thorns go also on their 'wings'. Also, "Sufah" is greater than Ru'ach. The Nimshal is, in addition to Sancheriv fleeing from Hashem, he will flee from his nation and country; in the end, his sons killed him.