The noise of a multitude in the mountains, like as of a great people; a tumultuous noise of the kingdoms of nations gathered together: the LORD of hosts mustereth the host of the battle.
The noise of a multitude in the mountains - namely, which separate Media and Assyria, and on one of which the banner to rally the hosts is supposed to be reared.
A tumultuous noise. The Babylonians are vividly depicted as hearing some unwonted sound like the din of a host: they try to distinguish the sounds, but can only perceive a tumultuous noise.
Of the kingdoms of the nations - Medes, Persians, and Armenians, composed Cyrus' army.