When it comes to justification, the Reformers rightly talked about a sharp distinction between the law and the gospel. In other words, our obedience to the law cannot help one whit in justification. The only thing that saves and justifies is the gospel. In Paul’s terms, a person is justified by faith and not by works (Rom. 3.28). Here’s how Luther explained it as he commented on Galatians 3.2.
“The Law and the Gospel are contrary ideas. They have contrary functions and purposes. To endow the Law with any capacity to produce righteousness is to plagiarize the Gospel. The Gospel brings donations. It pleads for open hands to take what is being offered. The Law has nothing to give. It demands, and its demands are impossible.”
One phrase sticks out and is one worth thinking about throughout our lives: “To endow the Law with any capacity to produce righteousness is to plagiarize the Gospel.” Brilliant.
See it here: Martin Luther’s Commentary on Galatians.