In his commentary on Paul’s Epistle to the Galatians, Martin Luther famously stated:
Here I must take counsel of the Gospel, I must hearken to the Gospel, which teaches me, not what I ought to do (for that is the proper office of the law), but what Jesus Christ the Son of God has done for me: to wit, that he suffered and died to deliver me from sin and death. The Gospel wills me to receive this, and to believe it. And this is the truth of the Gospel. It is also the principal article of all Christian doctrine, wherein the knowledge of all godliness consists. Most necessary it is therefore, that we should know this article well, teach it unto others, and beat it into their heads continually. For it is very tender, so it is soon hurt.
The quote is in response to the Galatians entertaining the idea that circumcision in addition to the work of Christ was necessary for salvation (e.g. Gal. 6:12). And while this was just one relatively minor work on the behalf of man it was enough to result in a false gospel (Gal. 1:6-9). Here Luther is speaking on Sola Fide or salvation through faith in the completed work of Christ alone and without human works. Sola Fide is so important that Luther rightly identified it as the principal article of all Christian doctrine. Indeed, without it there is no genuine Gospel or authentic Christianity. For what can man do to add to Jesus’ shed blood and death upon the cross? And even to believe that one could aid in his or her salvation is to take away from the rightful honor and glory belonging to Jesus alone.
This quote is often ended after the bolded text; no doubt for effect. However, the final line here is important to note. It is not that Sola Fide is tender in itself as it is a fundamental fact of reality. It is however tender in that man so quickly abandons it. In 1547, the Roman Catholic Church formally rejected Sola Fide at the Council of Trent, teaching that any who hold to it are to be anathema.[1] And while this is a stark example of the doctrine being hurt, the sinful nature of even Protestants and Evangelicals moves them to privately consider that they may need to be doing more to be saved. And to the extent that people believes this, they need to have Sola Fide beat into their heads.
[1] In particular, see canons 9, 12, 14, 23, 24, 30 and 33.
I recently took a course on Jewish History. I was horrified when I looked up Martin Luther’s work “Against the Jews and their Lies”. I then looked up his 95 theses as I was in wonder that a believer could make the statements he makes in that later work (“Against the Jews…”). His 95 theses seem to be predominantly about the practice of indulgences – not calling them out as unbiblical but rather he seemed more concerned for their effect on the poor. I couldn’t find a clear statement of the gospel in there. Admittedly I didn’t spend a huge amount of time on it (the course was packed with readings and assignments), but I wonder if you have looked into this shocking and conveniently ignored aspect of Luther’s ‘ministry’.
Early in his ministry Luther was an advocate for the Jews, and then toward the end of his life he took the position you identified in his infamous anti-Semitic work. I’m certainly not making any excuses for such evil. However, “Against the Jews and Their Lies” is poorly structured and comes off as written by a madman. I personally suspect something was going wrong with Luther’s mind.
It is true that the 95 theses were born out of a response to indulgences. However, the issue of indulgences was one of works being added to the Gospel. Luther plainly taught the Gospel in an especially powerful manner in sermon after sermon. His commentaries on Romans and Galatians are among the most powerfully written on the subject of the work of Christ and salvation through faith alone.
I see Luther as both deeply blessed and deeply flawed. He was a lion of the Reformation and a champion of Sola Scriptura and Sola Fide. At the same time Luther taught evil things that contributed to later horrific acts in Germany.