What is "Hass"?
Radak: Be silent.
Malbim: They will be silent when they see the revelation of Hashem in the future and His vengeance against those who pained Yehudah. Also Chabakuk said "Hass mi'Panav Kol ha'Aretz" (2:20) when he saw the vengeance against Bavel.
To whom does "Kol Basar" apply?
Rashi: All the other Nochrim.
What is the meaning of "Ne'or"?
Rashi: This is an expression of "Ha'irah v'Hakitzah" (Tehilim 35:23, i.e. awakening). Radak ? this is a Mashal, like one who wakes up from sleep, like "va'Yikatz k'Yashen Hashem" (Tehilim 78:65). Ne'or is Nif'al conjugation, in which the middle letter of the root is silent, like Navon and Nachon, even though there, there is a Kamatz under the Nun, and here there is a Tzeirei.
What is "Me'on Kodsho"?
Radak: It is Shamayim.
