Stephen Westerholm is an NT scholar who has taken the time to work his way through the primary sources--not only on Luther, but also on Augustine, Calvin, and Wesley (among others). I am finding his Perspectives Old and New on Paul: The "Lutheran" Paul and His Critics to be a superb resource--not only for understanding the history of the debates, but also in providing one of the most persuasive readings I've encounted on Paul's view of faith, grace, law, and works.
Here are his summary theses on Luther's view of the law.
- In our relationship with God, faith in his goodness rather than the good works we do is decisive.
- The law, like a mighty hammer, is meant to crush human self-righteousness and to drive human beings, made aware of their sinfulness, to seek mercy from the Savior.
- We are justified by faith in Jesus Christ, not by the works we do.
- Though believers are righteous in God’s eyes, they remain sinners throughout their earthly lives.
- The law must be banished from the thinking of believers when their relationship with God is the issue. Yet it must continue its role of identifying and judging their sin.
- God predestined believers to salvation.