What is the Nimshal of an axe priding itself over the one who chops?
Rashi: Hashem tells Melech Ashur, you should not have prided yourself for this, for you are only My axe, and I chop with you. I am paid via you from My enemies.
What is "Masor"?
Rashi: It is a saw. Radak - the root is Neser. The Nun is omitted, and there is a Dagesh in the Sin in place of it.
Why is the Mashal repeated?
Radak: It is to strengthen the matter.
Malbim: The ax, even though initially man lifts it, at the end it chops by itself (via gravity). The saw does not cut by itself at all. In the Nimshal, also the final conquest was via Hashem.
What is the meaning of "k'Hanif Shevet Es Merimav"?
Rashi: It is as if the staff waves itself and the hand of the one who lifts it. A staff does not wave itself, rather, the person [waves it]!
Radak: Melech Ashur is merely "Shevet Api" (5). "Merimav" is Elokim, which is plural, e.g. "Elokim Kedoshim Hu" (Yehoshua 24:19).
Malbim: The Kli does not move itself - all the more so it does not move the person that moves it! Melech Ashur claimed that he forces Hashem's strength according to his desire; he will conquer Yisrael and overpower Kel, their strength.
What is the meaning of "k'Harim Mateh Lo Etz"?
Rashi: The wood does not lift itself, rather, the person lifts it.
Radak: The wood will not be more than other wood; it will not grow more than it is now. Amidst its pride, it will perish.
Malbim: Will a staff say that it is not wood, rather, it has a Nefesh that moves by itself?! Melech Ashur said that he is not a person, rather, Kel - "Adameh l'Elyon" (14:14). This was foolish for four reasons. (a) He denied that all his strength and acts are Hashem' acts. (b) He denied also that Hashem gave to him the authority. (c) He thought that he will overpower the G-d of gods. (d) He became so foolish that he forgot that he is a person, and said "Adameh l'Elyon."