Either Jerusalem changed its name, or we've wandered into a production of The Tempest because Isaiah is now cursing someone or something called Ariel, which he is going to besiege and destroy at the same time as all his other enemies. How's he going to destroy it? The usual: fires, earthquakes tempests (v. 6). It's going to be as bad as when you fall asleep hungry and then dream that you're eating and wake up still hungry and realise you forgot to go to the store but it's okay because we live in a 24/7 world and not the Bronze Age, where not having any food REALLY meant you wouldn't eat that day.
People who don't believe him are blind and drunk and listening to false prophets. To convince them, he's going to perform some wondrous works of nature that will wipe away their memories.
Never forget that god knows everything and we are as the potter's clay: for shall the work say of him that made it, He made me not? or shall the thing framed say of him that framed it, He had no understanding? (v. 16).
Finally, god promises to do something nice instead of smiting and plaguing and burning shit down: he's going to make the crops grow in Lebanon, restore hearing to the deaf, make the blind see and make the meek and poor love him more. Politicians will be consumed. I guess this one hasn't come true yet. The point of all this? To make people who only murmured the words believe them.
Threats against those who would make a treaty with Egypt: A caravan carrying money to pay for mercenaries will have to cross a desert full of lions, snakes and fiery flying serpents (v. 6) will come to nought, because you just can't trust 'em. Why? John Locke says so. Whoops! Not for another 2000 years or so. But the thesis is the same: they don't believe in your god.
More pottery imagery: he shall break it as the breaking of the potters' vessel that is broken in pieces; he shall not spare: so that there shall not be found in the bursting of it a sherd to take fire from the hearth, or to take water withal out of the pit. (v. 14) The only solution is to repent. No matter what they do otherwise, flee on horses, even swift horses, god's horses will be faster.
But when they do repent, god will be forgiving and will teach them to be better and throw away their idols like a menstruous cloth (v. 22). Seriously Isaiah is completely obsessed with the female reproductive cycle. In exchange, they'll get rain, bread and fat cows and dead enemies, in this case the Assyrians, which they will celebrate. Then he'll burn the king at the stake.