There are people who try very hard to keep the law without the message of the gospel transforming them beforehand. Even if we look at even a Christian who's trying to keep theLaw, this conversation is such good news to that person. It's the same thing Paul is nailing in Romans 1 and 2: We all get nailed. We're hearing the last judgment. There is no one righteous, no not one all are condemned. And through faith, hearing the contrary verdict, you are righteous in Jesus Christ.