What does "Shem Hashem" refer to?
Rashi: His Gevurah, which will be fame for Him, what He will do to Sancheriv.
Radak: Melech Ashur's messengers blasphemed Hashem's name - it will come to take vengeance against him.
What is the significance of "Ba mi'Merchak"?
Rashi: He will fulfill what He promised a long time ago.
Radak: Melech Ashur thinks that it is as if Hashem is far away, and cannot harm him. He will come from afar!
Malbim: Sancheriv was Hashem's staff of anger against Yerushalayim. Externally, it looked like He was bringing him with fire, smoke and anger to eradicate Yisrael. Really, internally there was water of Chesed to extinguish the fire.
Why does it say "Masah" with a Hei?
Rashi: The Hei is extra, therefore there is no Dagesh 1 .
Radak: If it meant her [or its] Masa, it would have a Mapik Hei.
Why does it say "Koved Masah"?
Radak: The Masa (punishment) that Hashem will put on them will be Kaved (heavy) on them and hard to bear.
Why does it mention His lips and his tongue?
Radak: The matter is repeated in different words. Both of them refer to words of Nevu'ah about them.
Malbim: His lips are full of fury, i.e. He cursed, and His lips burn amidst great anger.
