God lovingly tells the people of Israel that he has already redeemed them. They can pass through rivers and fire, without drowning or being burned.
He will give away other nations—like Egypt and Ethiopia—in exchange for Israel. The exiles and offspring of Israel will be returned from all over the earth.
God says to gather together the people who are (paradoxically) blind but can see, and deaf that can hear, and gather all the nations together too.
God takes the stage: "Now that you're all here, go ahead and tell me about those other gods and how great they are. Oh, you can't? Because they're not?"
We're glossing, but that's the gist. God harps on how he is the only god, the only hope for salvation, and the only one who can tell the future.
He calls on all the nations to witness that he, and only he, is the Big-G God.
Out with the Old Out with the Old
God will destroy the Babylonian Empire, turning the Babylonian shouts of victory into lamentations.
He compares this, implicitly, to how he parted the Red Sea to deliver his people while drowning their enemies.
God tells the people not to regard the old ways, since he's got some brand new goodies coming their way. He's making a way in the desert and the wilderness, and even the wild animals are acknowledging him. (Seems new to us.) He'll give water to his people so that they'll praise him.
But instead of giving God some juicy sacrifices, the people just keep wearying him with their sins. He reminds them by saying that he hasn't given them a very tough burden to keep up.
Yet, God says he's going to forgive and forget. They can bring their case against him if they want and try to take God to trial ("I won't be offended, I promise." – God, his voice dripping with sarcasm), but their ancestors really were sinners (says God). They deserved the suffering that came to them.