The actual date of Martin Luther's conversion is disputed. Some place it before the posting of the Ninety-Five Theses; some put it before the Heidelberg Disputation. It is highly likely, however, that Luther’s conversion came in 1519. In reading the whole of the Ninety-Five Theses, it is clear that Luther still held on to a number of formative Roman Catholic doctrines. At that point, he was not in favor of jettisoning the whole of it; he sought instead to correct and purify it from the corruptions that he saw as creeping in during the 1200s through the early 1500s. The corruption culminated in the indulgence sale of Tetzel and Albert and the relic exhibit at Wittenberg. There is also Luther’s own testimony that his “breakthrough” came while he was lecturing through the Psalms a second time. Those lectures were given in the early months of 1519. Many years later, in 1545, Luther reflected on his conversion, and offered up an extraordinary account of this event, one that hinges on understanding the difference between the active and the passive. So, Luther tells us:
Meanwhile, I had already during that year returned to interpret the Psalter anew. I had confidence in the fact that I was more skilful, after I had lectured in the university on St. Paul’s epistles to the Romans, to the Galatians, and the one to the Hebrews. I had indeed been captivated with an extraordinary ardor for understanding Paul in the Epistle to the Romans. But up till then it was not the cold blood about the heart, but a single word in Chapter 1, “In it the righteousness of God is revealed” that had stood in my way. For I hated that word “righteousness of God,” which, according to the use and custom of all the teachers, I had been taught to understand philosophically regarding the formal or active righteousness, as they call it, with which God is righteous and punishes the unrighteous sinner.
Though I lived as a monk without reproach, I felt that I was a sinner before God with an extremely disturbed conscience. I could not believe that he was placated by my satisfaction. I did not love, yes, I hated the righteous God who punishes sinners, and secretly, if not blasphemously, certainly murmuring greatly, I was angry with God, and said, As if, indeed, it is not enough, that miserable sinners, eternally lost through original sin, are crushed by every kind of calamity by the law of the decalogue, without having God add pain to pain by the gospel and also by the gospel threatening us with his righteousness and wrath!” Thus I raged with a fierce and troubled conscience.
Nevertheless, I beat importunately upon Paul at that place, most ardently desiring to know what St. Paul wanted. At last, by the mercy of God, meditating day and night, I gave heed to the context of the words, namely, “In it the righteousness of God is revealed, as it is written, ‘He who through faith is righteous shall live.’” 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 merciful God justifies us by faith, as it is written, “He who through faith is righteous shall live.” Here I felt that I was altogether born again and had entered paradise itself through open gates. There a totally other face of the entire Scripture showed itself to me.
Thereupon I ran through the Scripture from memory. I also found in other terms an analogy, as, the work of God, that is what God does in us, the power of God, with which he makes us wise, the strength of God, the salvation of God, the glory of God. And I extolled my sweetest word with a love as great as the hatred with which I had before hated the word “righteousness of God.” Thus that place in Paul was for me truly the gate to paradise.