What noise did the land make?
Radak (8): This is a metaphor for Am ha'Aretz' fear of the kings and the nations.
Radak: The entire verse discusses Matan Torah.
Did Shamayim drip?!
Radak #1: This is a metaphor. Shamayim darkened on the enemy; a rainy day is dark due to clouds. And so it says in David's Shirah "Chashras Mayim Avei Shechakim" (Shmuel II, 22:12). This is a metaphor for the affliction that will come on the enemy.
Radak #2: There was a little rain on the day of Matan Torah.
Why does it say "Zeh Sinai"?
Rashi: Also Sinai made noise due to Hashem Elokei Yisrael.
Radak: The nations 1 and the mountain made noise on the day of Matan Torah - "va'Yecherad Kol ha'Am Asher ba'Machaneh", "va'Yecherad Kol ha'Har Me'od" (Shemos 19:16, 18).
Malbim: Hashem became known in these regions from when He descended on Har Sinai. Then, they saw His honor. Therefore, the land was noisy again when He appeared a second time.
The verse that Radak cites shows only that Yisrael were afraid! (PF)
Why does it say "Mipnei Elokim Elokei Yisrael"?
Malbim: Hashem became known in the Midbar as Elokei Yisrael, due to the miracles and wonders that He did for them in the past.
