In the second chapter of Luther on the Christian Life Trueman explains Luther’s important theological development at the Heidelberg Disputation. This disputation took place early in Luther’s career as a reformer. The significance of this event lies in the fact that it gives us a glimpse of Luther’s thought as it was in the process of maturing. Much of the theology of the Reformation can be found here in seed form in Luther’s Heidelberg theses. To help us understand this event, Trueman provides a little historical background. In April of 1517 Luther was given opportunity to present his theology at a convention of the Augustinian order held at Heidelberg. Luther’s presentation was carried out in the form of a disputation. The disputation was a common method employed in the middle ages to address questions of theology and philosophy. In this format a number of theses were defended and an opponent was appointed to argue against the theses presented. At the Heidelberg Disputation one of Luther’s colleagues, a fellow Augustinian monk by the name of Leonhard Beier defended the theological points Luther had prepared for the disputation. These points covered a variety of theological and philosophical questions but centered on Luther’s distinction between the “theologian of glory” and the “theologian of the cross.” We do not use these terms today. Likely many readers have never heard of them before. For our benefit, Trueman devotes the second chapter to explaining this important distinction in Luther’s budding theology.
The first thing we need to understand is to whom exactly Luther is referring when he speaks of these theologians. “Theologian of glory” and “theologian of the cross” are titles which Luther used describe two different groups of Christians who had two very different approaches to the Christian life. These terms do not refer to any particular individuals, rather Luther uses them to characterize, compare, and contrast his own Christ-centered view of the Christian life with the common works-centered view prevalent in his day. How do Christians think about God? How do they conceive of their relationship to God? How do human works relate to God’s grace? Such basic questions the theologian of glory and the theologian of the cross answer very differently. The theologian of glory thinks about God by looking at appearances, that is, by looking at the way things work in the world. The theologian of glory looks at the way humans relate to one another and on that basis draws conclusions about how humans relate to God. For example, when approaching the question of how we become righteous before God, the theologian of glory reasons that just as people are rewarded for doing good deeds in human society so too God rewards Christians with eternal life for their good works so long as they do the good they are capable of doing to the best of their ability. Merit operates within the realm of human relationships. Therefore it is inferred to operate in the divine-human relationship too.
On the other hand, the theologian of the cross looks beyond appearances to the inward and true reality revealed in the Gospel. He looks at everything from the perspective of God’s revelation and the mystery of the cross. This is important for Luther’s understanding of sin and righteousness. The theologian of glory confuses outward righteousness with true righteousness. The theologian of glory thinks that he is righteous because he has done good works to the best of his ability. Such a man does not understand the depth of his sin or what true righteousness actually is. He underestimates his sin and overestimates his own works. On the contrary, the theologian of the cross understands that he is a sinner and that all his good works contribute nothing to his salvation. Indeed they profoundly worthless. This knowledge of his own sin drives the theologian of the cross to Christ. In Christ he seeks all of his righteousness: not his own, but the alien righteousness of Christ. In Christ alone he trusts; not in works, not in merit, in the cross of Christ alone. Thus Christ’s cross and the truth of justification by faith alone is the lens through which the theologian of the cross looks at all of life. Naturally, this has tremendous implications for living the Christian life. This perspective offers the child of God true assurance of God’s forgiveness and reconciliation. It affords him genuine comfort that God is not a God of wrath toward him, but One of love, the kind of love exemplified on the cross. Indeed, the theologian of the cross sees God’s love in an entirely new light. Rather than trying to court God’s love by doing good works, the theologian of the cross recognizes that God does not set His love upon him because he is attractive in and of himself. Rather, God’s love makes His people lovely. God seeks out sinners who are of themselves repulsive and sets His love upon them, powerfully and efficaciously transforming them into beautiful and holy saints. Only then do God’s people respond to God’s love by doing good works as an expression of their gratitude. Therein lies the source of Christian’s good works. The true good works of the Christian life are the thankful deeds of the beloved, not the meritorious acts of those seeking to court divine favor. For Luther, to live the Christian life means, at its heart, to live one’s life thankfully and fully out of the power of the cross. Such is true Christian devotion.