Isaiah 21:1,2 - An invader comes from the land of terror

21:1,2

Babylon was to be destroyed twice, in 689 BC and 539 BC. The 689 BC defeat is the one of immediate relevance, though the 539 BC is more in view in the latter half of Isaiah. At the time Babylon was captured by Assyria in 703 BC. There were some in Judah who had hoped Babylon might help them against Assyria. So in Isaiah there are two natures to the anti-Babylon prophecies. Here the message to Judah is that they are a vain hope of salvation. Later the message to Israel is that your oppressor will be defeated.

Elam was a recurrent source of trouble for Babylon, though Elam would eventually be defeated by Assyria. The Medes were instrumental in the final defeat of Babylon in 539 BC, apparently with help from Elam.