Why does it say "Hine Al he'Harim"?
Radak: When Sancheriv died, they announced in Yehudah that they can dwell in their cities like initially, and they will go to celebrate the festival in Yerushalayim and offer their Korbanos and pay their vows.
Malbim: This king wanted to humble Yehudah; they feared him. The tidings came of his fall. According to the opinion that it was in the days of Menasheh, it is explicit in Divrei ha'Yamim II, 33:11 that generals of Melech Ashur took Menasheh to Bavel in chains; he prayed to Hashem, and He returned him to his kingship. Balizas, the general of Bavel, which was then under Ashur, took him. When he rebelled against Melech Ashur, he returned Menasheh. Menasheh vowed to serve Hashem 1 . Heralds came to tell that there is no fear of the enemy 2 .
Malbim: Tehilim 66 discusses this. "va'Sotzi'enu la'Rvayah; ? Ashalem Lecha Nedarai; Asher Patzu Sefasai" (12-14).
Malbim: I mentioned that based on chronicles, it seems that this was long before Menasheh. We must say that Sardanafal intended to harm the 10 tribes. It is not mentioned in Tanach, for he did not fulfill it.
What do we learn from "Shalemi Nedarayich"?
Rashi: What you vowed to Hashem if He will save you from Sancheriv - pay it, for now you were saved!
Malbim: When Menasheh returned to be king and repented, all can celebrate the festivals and pay what they vowed during the affliction, for the Mizbe'ach was rebuilt.
Who will not pass in you any more?
Rashi: That wayward one (Sancheriv).
What do we learn from "Kulo Nichras"?
Rashi: He and his seed [were wiped out].
Radak: His sons fled; [Ashur] will not come again.
