הָרִ֥ים נָזְל֖וּ מִפְּנֵ֣י יְהוָ֑ה זֶ֣ה סִינַ֔י מִפְּנֵ֕י יְהוָ֖ה אֱלֹהֵ֥י יִשְׂרָאֵֽל׃
The mountains quaked at the presence of the LORD, Even yon Sinai at the presence of the LORD, the God of Israel.
Rashi on Judges
Mountains streamed. Like streaming water—they dissolved.
Metzudat David on Judges
The mountains flowed from the greatness of the shaking, and they dripped sweat.
Metzudat Zion on Judges
a matter of dripping as in Bamidbar 24: 7: "Water drips from its roots."