The Capture of Babylon. This prophecy describes a siege and capture of Babylon by Elam and Media. It is almost universally considered to have been written shortly before the capture of Babylon by Cyrus in 538. The attempts made by a few critics to refer it to a capture of Babylon by Assyria in Isaiah's time 710, 703, or 696 have not been successful. The title wilderness of the sea is difficult. Possibly the point is that Babylon is to become a marshy desert (Isaiah 14:23). LXX omits of the sea.
The army of the invader sweeps into Babylon from the desert, the terrible land which separates Babylon from Elam, like as a whirlwind sweeps over Judah from the Negeb. A distressing vision is revealed to the prophet; since Babylon treats the vanquished so brutally, Elam and Media are bidden besiege it, for Yahweh has decreed that the sighing of her captives shall be made to cease. The prophet is overwhelmed with pain and dismay; far other than he anticipated is the twilight that he desired, the still evening hour when the spirit is exalted to receive visions or other Divine communications. For before the captives can be delivered there are the horrors of war and of the siege to be endured, in which they must suffer severely. He now describes the state of things in Babylon with all the vividness of the immediate impression of his vision. He sees the foe rush on Babylon, he sees the unreadiness of the Babylonians for the conflict. They are feasting when the foe is upon them. Next the seer describes how the vision has come to him. The watchman is the prophet himself in his trance condition. The description casts an interesting light on the psychological character of this state, and on the mode in which revelation was mediated (p. 430). Similar distinctions in self-consciousness are familiar to students of anthropology and psychology. The watchman is bidden listen very attentively, when he sees a troop come in sight. The troop is the army which is to attack Babylon. For a long time nothing happens, and he cries out in his impatience. At last the appointed vision comes, and he divines that Babylon has fallen. The prophecy concludes with words addressed to Judah. The metaphor refers to the severe treatment that Judah has undergone at the hands of the Babylonians.
Isaiah 21:5. set a watch: the rendering is very uncertain. Perhaps we should accept mg.
Isaiah 21:8. as a lion: perhaps a metaphor for impatience, but the text is corrupt. Read either I see or in my ears.