Whom does this address?
Rashi: The enemy.
Radak #1, Malbim: If this consolation is in the days of Chizkiyah, it addresses Sancheriv.
Radak #2: If this consolation is in the days of Mashi'ach, it addresses the king of the Goyim at the time, i.e. the fourth kingdom in Daniel's vision.
Why does it say "Shoded v'Atah Lo Shadud u'Voged v'Lo Vagdu Vach"?
Rashi: You constantly plunder, and you are not plundered. You constantly betray, and no one betrays and despoils you.
Malbim: Why do you plunder? You were not plundered! Why do you betray nations that made a Bris with you? They did not betray you!
What is "ka'Hasimcha"?
Rashi: When you finish [plundering those that it was decreed to be plundered via you, you will be plundered].
Radak: When your plundering finishes, you will be plundered 1 . The time will come for you to be broken, and your kingship will be finished. The root is Tamam; the Dagesh in the Tov is omitted, and a Mem is omitted.
Malbim: This is like it says "Ki Yevatza Hashem Es Kol Ma'asehu b'Har Tziyon? Efkod Al Pri Godel Levav Melech Ashur" (10:12).
What is "ka'Nelosecha"?
Rashi citing Menachem: This is like "Lo Yateh la'Aretz Minlam" (Iyov 15:29). The first Mem in Minlam is from the root; sometimes it is omitted (like here), like the Mem in Ma'amar and Mada. Based on context, perhaps it refers to eradication. There it means that the eradication decreed on them will not be lean to the ground to get weaker and nullified. Rather, it will get stronger.
Radak: It should say k'Hinlosecha; it is Hif'il. It is like k'Hishlimecha (when you finish). Also "Lo Yateh la'Aretz Minlam" refers to their completion and purpose.
Who will betray him in the end?
Malbim: Sancheriv's sons killed him via the sword.
