Our speaker invites everyone to turn their attention back to God, "the rock from which you were hewn," the same God of their ancestors.
He says that God will make the wilderness and the desert surrounding Zion into a garden as nice as Eden.
God's voice breaks in, saying that he will save the people swiftly. Heaven and earth will both vanish, but his salvation will endure forever. With a little sprinkling of ultimate justice and righteousness.
Righteous people shouldn't worry about the naysayers who make fun of them—they're just going to be devoured like wool getting munched on by moths.
Some Good Ol' Fashioned Serpent Wrastlin'
The speaker calls on God to awake and reveal his strength again, since he was the same person who killed the evil sea serpent Rahab and dried up the sea so that Israel could cross and return to Zion and salvation.
Now, God's voice comes back into the prophetic monologue. He is the one who comforts Israel, and he's confused as to why they would be afraid of mere mortals (like the Babylonians). After all, if they get into any trouble, they should know that they're going to get released from oppression right away.
That said, Israel has drunk from the bowl of God's wrath, making it stagger around like someone totally deluded. Its children are all caught by God's wrath, too. So who can save Israel?
God will give the cup of wrath to Israel's enemies instead, and Israel will receive mercy from now on. Probably one of the few times that someone was pleased to have their beverage confiscated.