An interesting take on the historical context of the Damascus prophecy here.
Aram, Assyria, Babylon: The Structure of Isaiah
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Three waves of Gentiles flood Judah in the book of Isaiah.
The first threat is from Aram and Israel, from Syria and the Northern kingdom. Assyria is the rising power to the east, and that power is threatening to overrun the nations to the west of Assyria. The kings of Aram and Israel want to resist the Assyrians, and so they form an alliance against the Assyrian empire (Isaiah 7-8) and they want to bully Judah into joining that alliance."
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"This was the biggest crisis of Isaiah’s lifetime, and this event is at the very center of the prophecy of Isaiah. Israel was already destroyed, and it would never recover. The northern kingdom never had a return from exile like the Southern kingdom would have. No dynasty of the Northern kingdom was restored. It’s speculation, but if Assyria were to take the southern kingdom, it might well mean the death of the Southern kingdom."
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The Aramean threat doesn’t do much damage. They will not succeed in their plans. This is the thrust of the prophecy of Immanuel to Ahaz. Damascus, the capital of Syria/Aram, will not prevail over Jerusalem, and Samaria’s head will not be able to overcome the head of Judah, who is Yahweh.
But the promise that the Aramean threat will be broken is shadowed by another threat, the threat of the second enemy, Assyria. The same prophecy and sign of Immanuel not only signifies the deliverance of Judah from Aram/Israel, but also the threat of the Assyrian invasion, which will be much more devastating than the Aram/Israel threat."
The chiastic structure of the book of Isaiah is interesting, one of the more interesting, in fact, for those inclined to look into it.
