What is the meaning of "Harim ka'Donag Namasu"?
Rashi: Mountains will melt like wax - "v'Nehersu he'Harim v'Naflu ha'Madregos" (Yechezkel 38:20).
Radak: 'Mountains' is a metaphor for kings of the nations.
Malbim: The verse depicts that the lightning is a messenger of His Hashgachah. When it leaves the cloud and darkness, where is Elokim who supervises, and reaches the mountain tops, they will melt like wax due to fire.
Why does it say "mi'Lifnei Hashem" and "mi'Lifnei Adon Kol ha'Aretz?
Malbim: They will recognize that the lightning melting the mountains is from Hashem, and not due to Elilim. All Ba'alei ha'Tzava 1 attribute all consequences of nature to Bnei Elim, and they attributed divine power to them. They had a god for each force of nature, and a master over each nation and climate - a particular star that influences on it. Now they will see that there is one Master over the entire land who does this.
Moreh ha'Nevuchim (3:29) mentions them.
