This probably refers to earthquakes and gives the impression that the mountains quaked because they were very afraid of Yahweh. Alternate translation: "The mountains trembled in fear" (See: [[rc://en/ta/man/translate/figs-personification]] and [[rc://en/ta/man/translate/figs-explicit]])
When Moses and Israel were at Mount Sinai, it quaked. Alternate translation: "long ago, even Mount Sinai quaked" (See: [[rc://en/ta/man/translate/figs-explicit]])