From the first chapter of the book, Isaiah is traditionally related to a king of Judah, Amaziah, and this part of the book calls a judgement against Judah.
We can have everything and not see it. God is on our side. He has given of himself so that you may walk with Him. And yet you, as your people have done before you, have squandered his gifts. You have taken pleasure in His blessings without acknowledging the source of them. And there will be a reckoning. A reckoning you can avoid.
You can keep and indulge in your blessings, but you need to pay your due. He wants your praise, but that is meaningless, an insult, if you don’t do what is right. And He has given you His Word so you know what is right. But you know what is wrong if you Know God, and allow him into your heart, to be the centre of our life. You can see what is just, and what is not.
Isaiah's writing is lyrical. The contrast of red blood and white wool is strong. The offer of a legal settlement is administrative.