This excerpt is adapted from Stephen Nichols’ contribution in The Legacy of Luther.

Nestled along the Rhine River, Heidelberg was the site for the General Chapter, or assembly, of the Augustinian Order in May 1518. Staupitz, the general vicar (or head) of the order, seized this moment for Luther to speak to the crisis caused by the Ninety-Five Theses. Luther responded by drafting a new set of theses, the Twenty-Eight Theses for the Heidelberg Disputation. Though far less known than the theses nailed to the church door, these theses are the most important text during this period of Luther’s development. At one point in his life, Luther would declare, “Crux sola est nostra theologia,” meaning, “The cross alone is our theology.” That singular expression crystalizes what Luther was aiming at in the Twenty-Eight Theses at Heidelberg. Before enumerating the theses, Luther wrote a short introductory paragraph as a preface. The preface is essential for understanding the work as a whole. Luther starts off by noting that he distrusts “completely our own wisdom,” and so he relies on and draws from “St. Paul, the especially chosen vessel and instrument of Christ, and also from St. Augustine, his most trustworthy interpreter.”

The Latin expression ad fontes, “to the sources,” served as the Renaissance battle cry. It meant going back to the originals, or the fountainheads. This can be seen in the revival of Greco-Roman architecture and art. It can be seen in the desire to read Plato and Aristotle directly, instead of reading layers of medieval interpretations of Plato and Aristotle. In theology, it meant reading the Bible, and Augustine too, rather than reading layers of commentary on the primary sources. Ad fontes of the Renaissance is mirrored in the counterpart sola Scriptura of the Reformation. Luther’s short preface declares the sources of his teaching—Paul and Augustine. He also admits—and we need to see this—that the hearers and readers of the Twenty-Eight Theses will have to determine how “well or poorly” Luther deduced them from Paul and Augustine. Luther’s source, however, was the fountainhead. It was the “source” that led him to see how wrong the practice of penance became back in October 1517. The more Luther looked to the sources, the more wrong he saw in the church of his day.

After the short paragraph preface comes the Twenty-Eight Theses. They compare and contrast what Luther calls a “theologian of glory” and a “theologian of the cross.” Typically, we associate glory, especially the glory of God, with good things. In this case, however, Luther sees a theologian of glory as a bad thing. A theologian of glory is the same as the false prophet who declares peace in thesis 92 of the Ninety-Five Theses. In Heidelberg thesis 21, Luther writes, “A theologian of glory calls evil good and good evil.” In using the term glory, Luther is talking about the inane idea that humanity itself has its own glory, or that humanity has the ability to please God and to perform righteousness. This idea leads the theologian of glory to disdain God’s grace. Divine grace is the good thing that a theologian of glory calls evil. In short, the theologian of glory exults in human ability and in works-righteousness. Standing in contrast to the theologian of glory is the theologian of the cross. The theologian of the cross starts with us—more specifically, with our misery. Thesis 18 reads, “It is certain that man must utterly despair of his own ability before he is prepared to receive the grace of Christ.” Consequently, thesis 25 informs us, “He is not righteous who does much, but he who, without work, believes much in Christ.”

The theologian of glory actually does far worse than call grace evil. The theologian of glory, the one who trusts in human ability and trusts in the accumulation of merits and works, actually despises Christ. Then, in the last of the Twenty-Eight Theses, Martin Luther writes what very well may be the most beautiful sentence he ever wrote: “The love of God does not find, but creates, that which is pleasing to it.” The love of God will never find anything pleasing to it in us, because we are all sinners who are unrighteous and utterly distasteful to the Holy God. And so, God makes us righteous. He (re)creates us.

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.

This is the gospel. This is the doctrine of justification by faith alone. The key here is that Luther is passive. Christ takes on his sin. Christ achieves righteousness, in His obedience in His life and in His death on the cross. This was Luther’s discovery. Christ did it. All of it.