Why does it say "Kol Hashem ba'Ko'ach"?
Rashi: At the time of Matan Torah, Hashem limited His voice according to Yisrael's ability [to hear]. "Veha'Elokim Ya'anenu v'Kol" (Shemos 19:19) - [equal to] Moshe's voice (Brachos 45a).
Radak: At Matan Torah, Hashem's strong voice first went to the water to weaken its strength, and afterwards it came with honor, to Yisrael.
Radak (11) #1: Hashem's voice will come to them with His strength, beauty and honor, until they will recognize that all their strength is nothing, and they have no power to be saved from Him. The Mizmor uses the metaphor of destroying via noise, for man does not see it. He panics, falls and dies. So Hashem will fight against them without a sword or spear.
Radak (11) #2: It refers to the war of Gog and Magog - "v'Nishpateti Ito b'Dever uv'Dam v'Geshem Shotef..." (Yechezkel 38:22).
Malbim: Now was aroused an explosion, flood and hailstones - awesome forces, beautiful and frightening appearances on every side.
What is the meaning of "be'Hadar"?
Radak: So [Yisrael] could bear it. Even so, it confounded them - "v'Al Tedaber Imanu Elokim Pen Namus" (Shemos 20:16).
Radak (11): For Nochrim, Hashem's voice kills them; for Yisrael, it is for beauty; it does not harm them.
