A crucial event in Martin Luther’s life occurred in Wittenberg: his conversion. There is some dispute over the date of this event, as some scholars claim it took place before his posting of the Ninety-Five Theses in 1517 and others believe it happened in the 1520s.

Luther provided his own testimony of the event in a preface to a collected edition of his Latin writings published in 1545. He wrote that he had lectured through Romans, Galatians, and Hebrews and was giving his second series of lectures through the book of Psalms. We know that those lectures took place in 1518. It might surprise some people that Luther nailed the Ninety-Five Theses to the church door before he was converted. One of the lines we see in the introduction to the Ninety-Five Theses is, “Out of love for the truth and the desire to bring it to light.” That’s what Luther was questing after. He was searching for the truth—specifically, the truth of the gospel.

It was a rough road for Luther to get there. He was reading Romans and came across a phrase in Romans 1:17: “the righteousness of God.” Luther recounted his thoughts as he read that passage: “I hated the righteous God who punishes sinners. Thus, I raged with a fierce and troubled conscience.” When he saw those words, “the righteousness of God,” Luther thought it referred to a righteousness that he had to achieve. He also knew that no amount of good works or striving would achieve a level of righteousness that would satisfy a holy God. This left him in utter despair. Nevertheless, Luther had to keep reading, and so he kept pounding at this door of truth.

Eventually, God revealed to him that this righteousness is not something that we actively achieve, but rather something that God achieves. We are passive. Luther wrote, “There I began to understand that the righteousness of God is that by which the righteous lives by a gift of God, namely, by faith. And this is the meaning. The righteousness of God is revealed by the Gospel, namely, the passive righteousness with which the merciful God justifies us by faith. Here, I felt that I was altogether born again and the very gates of paradise opened up before me.”

We refer to this as the Deichbruch or the breakthrough in Luther’s life. This was his conversion. Gone was the darkness and now was the light. Luther would also recall, “I extolled that sweetest word, that word, ‘The righteousness of God.’ I extolled that sweetest word with a love as great as the hatred with which I had hated the word, ‘The righteousness of God.’”

Luther came to realize that there was nothing he could do but that Christ has done it for him. In fact, not only did Christ do what Luther could not, He also undid what Luther did. He paid for our sin on the cross and He achieved perfect righteousness by His life of obedience. He earned—He achieved—the righteousness of God. And we apprehend it not by works but by faith alone. Luther came to learn that this was the gospel. This was the meaning of the crucial phrase in Paul’s epistle to the Romans, “the righteousness of God.” By God’s mercy, Luther learned that in Wittenberg.