What is the meaning of "me'Im Hashem Tzevakos Tipaked"?
Rashi: After you will lower and whisper your words, I will save Ari'el.
Radak: How will this great decree come suddenly? It is because it is from Hashem.
Will there be thunder and earthquake?
Rashi: Yes, in order to save Ari'el.
Radak: The plague that will strike [Machaneh Ashur] is compared to thunder and earthquake.
Malbim: They are the two matters mentioned above (28:21) - "ch'Har Peratzim Yakum Hashem" is the earthquake, and "k'Emek Giv'on Yirgaz is thunder.
Why does it say "v'Kol Gadol"?
Malbim: It will not be covert. Here it depicts three camps that Elokei Yisrael saw (Melachim I, Perek 19) - wind, noise and fire. Corresponding to the fourth, a soft voice, it says that here there will be a loud voice.
What will the wind do?
Malbim: It will make the flame flare up - "v'Hayah Ohr Yisrael l'Esh" (10:17).