Charles Ellicott Commentary Judges 5:5

"The mountains quaked at the presence of Jehovah, Even yon Sinai at the presence of Jehovah, the God of Israel." — Judges 5:5 (ASV)

Melted. — Literally, flowed away — a powerful poetic image. (Isaiah 64:3; Psalms 97:5 — melted like wax.)

Even that Sinai. — Rather, even this Sinai, as though Deborah actually saw the sacred mountain before her. The boldness of the expression leaves no difficulty in supposing the meaning to be that even as Sinai was moved (Psalms 68:8), so the mountains of Edom seemed to melt away before the march of Jehovah and the banners of Israel.