What does this Mizmor discuss?
Radak (3, from Mechilta Yisro): It is about Matan Torah.
Radak (11) #1: It discusses Hashem's wonders seen in the land (stars, rain, lightning...)
Radak (11) #2: It refers to the days of Mashi'ach.
Malbim: It is about the Churban and the flood that Hashem sent at that time, and a great storm, flames and lightning bolts that uprooted cedar trees and broke rocks. This was all around the borders of Eretz Yisrael. All four 'elements' (earth, fire, wind and water) came to destroy Eretz Yisrael. When they reached the land, the bowed and feared Melech ha'Kavod who dwells in His Heichal. The fire and the storm abated; Hashem blessed His nation with Shalom.
What is the meaning of "Havu la'Shem"?
Rashi: Prepare for Hashem.
Rashi citing Menachem: It is an expression of giving.
Malbim: Prepare to be Hashem's messengers.
Who are "Bnei Elim"?
Rashi (from Rosh Hashanah 32b): The children of "Eilei ha'Aretz" (Melachim II, 24:15). This is the source to say [a Brachah in Shemoneh Esre about the] Avos.
Rashi citing Menachem: Elim are officers.
Radak (11): Elim are powerful ones, i.e. angels; Bnei Elim are stars - they are like sons of angels. Ibn Ezra - it mentions stars, for rain falls according to their arrangement, with Hashem's help.
Malbim: The great forces of nature.
Why does it say "Havu la'Shem Kavod va'Oz"?
Rashi (from Rosh Hashanah 32b): This is the source to say [Birkas] Gevuros.
Radak: Give honor to Hashem. "Tenu Oz lEi'lokim" (68:35) - giving is via speech and thanks. The matter is repeated to strengthen it.
Malbim: Via [the great forces of nature,] Hashem's honor and strength are seen.
