Charles Ellicott Commentary Isaiah 13:4

"The noise of a multitude in the mountains, as of a great people! the noise of a tumult of the kingdoms of the nations gathered together! Jehovah of hosts is mustering the host for the battle." — Isaiah 13:4 (ASV)

The noise of a multitude ... — The prophet hears, as it were, the tramp of the armies gathering on the mountains north of Babylonia (possibly the Zagros range, or the plateau of Iran, or the mountains of Armenia; but the prophet’s geography was probably vague) before they descend to the plain and march against the haughty city. .