The finality of God's decrees must be lived with and accepted. No one out muscles God. It is an impossibility. What God purposes will happen, both in His judgment and in His goodness to us. We tend to shudder at judgment's prospects. But we can also take heart that His good graces are also as irrevocably final.
When Isaiah wrote this he was referencing the coming judgments on Assyria and Babylon. Those empires would fall. It would be justice for their brutality. But that same judgment would bring joy and deliverance for the remnant of Israel. So in His decree is both pain and pleasure, judgment and joy, gravity and goodness.
When people don't like the stern judgments in the prophets, they forget that the "B-side" of judgment is deliverance. God's justice always brings good things to the world. The ultimate expression is found in the cross, where my sin was judged in the death of my Lord Jesus Christ so that my life might be found in His resurrection.