Radak: Sancheriv thought that there is no Master over him - "b'Cho'ach Yadi Asisi uv'Chachmasi Ki Nevunosi" (13). The Navi says, ha'Adon Hashem Tzevakos is the Master of legions above and below.

Malbim: All legions are in His hand. He will do a miracle to cut down this great forest of Sancheriv's camp.

Rashi: That night.

Rashi: He will split Porosav, the branches of the tree, with a saw that cuts branches. "Purah" is not an expression of a winepress, like "Purah Darachti" (63:2), for that is with a Vov, and here it has an Aleph, like "va'Te'erachnah Porosav" (Yechezkel 31:5). "Mesa'ef" is cutting off branches, like "v'Chalah Se'ifeha Poriyah" (below, 27:10). Ma'aratzah is a Kli that breaks branches.

Radak: Hashem will make Melech Ashur's army fall. His camp is compared to a forest full of tall trees. "B'Ma'aratzah" is with a strong hand.

Malbim: One who cuts wood from the forest for his need, first he cuts thicket, which is not so important, and low trees. Here, He cuts in order to destroy. Just the contrary, first He cuts the branches that give Pe'er (beauty) to the tree. And He does not cut with a scissors to make them even, like is normally done for beauty, rather, with Ma'aratzah, to destroy.

Rashi: The kings and officers.

Radak: They are the tall trees. This is a metaphor for the great officers with [Sancheriv].

Rashi: Gidu'a applies only to trees and hard matters.

Malbim: Every tall tree will be cut. Only low bushes will remain.