Two kinds of power are on display in Isaiah: human power and the (so much greater) power of God. Human beings continually strive to use their power to do things like conquer the world (what the Assyrians and Babylonians do), only to see it snatched away from them, proving that God holds the only power that matters. Whenever a human being starts to assert his or her power and make the sort of classically boastful statements that Biblical villains—like Sennacherib—tend to make, it's time for an immediate smackdown. But the same is true even for the small-time criminals described in Isaiah, those powerful people who won't pay their workers a decent amount of money, and cheat them, but pretend to humble themselves before God in the temple. They all get their karmic beatings, thanks to the just power of God.
Questions About Power
How much power is it acceptable for a human being to have? When does that power start to aggravate God? Why do you think so?
Does all power come from God? Are there any other sources of power in Isaiah's universe, aside from God?
How should power be exercised (either according to Isaiah or according to you)?
What is God ultimately trying to use his power for? Why do you think so?