Even though destruction is sure and will approach Jerusalem (v. 12), yet Jerusalem (“Zion”) need not fear. Assyria will certainly threaten it (lift up his staff, as the Egyptians had done earlier) but the threat will be temporary (v. 25) and Jerusalem will be saved. Instead, Yahweh will turn his wrath upon Assyria.
However, this text also has an eschatological level of meaning. In that context, Assyria is not a historical nation, but rather a symbol for Yahweh’s enemies. Like Isaiah’s other dual prophecies, this one applies to two time periods: to events contemporary with Isaiah and also to the Messiah’s triumphal entry, which will result in the downfall of Israel’s enemies.