The supreme authority for Christian theology is the Triune God and the Holy Scriptures through which he speaks. The Lutheran Scholastic theologians, beginning with Johann Gerhard, spoke of theology’s “principle of being” (principium essendi) and principle of knowledge (principium cognoscendi). Theologians in the Protestant tradition often speak of Holy Scripture as the supreme authority in Christian theology. This is not incorrect. But it should be qualified by recognizing along with the Lutheran Scholastics that although Holy Scripture is the inspired Word of God, its authority ultimately rests on the authority of the Triune God who through it addresses humanity.
Affirming that Holy Scripture is the foundation and source of all true Christian theology does not rule out the reality that God speaks through other mediums. Indeed, Luther speaks of all creatures as God’s masks, channels, and created words through which God addresses humanity. The eighteenth-century Lutheran philosopher Johann Georg Hamann spoke of humanity as enveloped by God’s address through creation.
Nevertheless, we must make a distinction between God’s auditory and visible words. God acts on his creatures through the physical mediums of the whole of creation. However, God only tells humans how they are to know him in these physical mediums through his auditory Word. God’s auditory words were revealed to the prophets and the apostles and written down in the Bible. We know that the Scriptures are the inerrant Word of God because Jesus Christ affirmed their authority and proved his own by rising from the dead.
The Clarity of Scripture
God’s authoritative Holy Scripture only is read and appropriated correctly only when it is read in light of the message of unilateral grace in Jesus Christ. In his seminal work, The Bondage of the Will (1525), Luther speaks of Holy Scripture’s “inner-clarity” and “external-clarity.” Scripture must possess a clarity understandable to believers serve as the basis of Christian theology. Nevertheless, the clarity posited by Luther and the other Magisterial Reformers should not be confused with a kind of naïve epistemic realism that assumes that humans can simply sit down and read the Bible without imposing their own presuppositions or distortions.
As a result, Holy Scripture can only be read and correctly appropriated when theologians attend to the historical-grammatical meaning of the text. The reader must have the right presuppositions to perceive the clarity of Scripture. The work of the Holy Spirit on the heart and mind of the believer makes this possible. Importantly, the Spirit’s activity constitutes the inner-clarity of Scripture. Therefore, basing himself on 2 Corinthians 3, Luther argued that only the work of the Spirit can cause the believer to recognize the unity of Scripture in Jesus Christ and clarify the meaning of the Bible. The ultimate aim of all Scripture is the revelation of God’s unconditional grace in Jesus Christ. Without perceiving this end, the reader cannot correctly construe the meaning of individual passages. Consequently, individual articles of the faith will ultimately become distorted.
Christian theology must also rely on the external-clarity of Scripture since the words of the Bible function as its cognitive-principle. The external-clarity of the Bible is the historical-grammatical meaning of the text when read within the context of an individual book. Additionally, external-clarity relates to understanding the whole of Scripture within the larger context of the unified creedal narrative of the Faith (analogia fidei).
Of course, knowledge of biblical languages and their historical contextual meaning does not render every individual text of the Bible absolutely clear. There are many passages that are difficult to translate or understand even in their original historical context. Nevertheless, no doctrine is unclear. The unity of the faith and the clarity of individual doctrines can be discerned through the grammatically clear passages that teach the specific doctrines of the faith. Philip Melanchthon called these the sedes doctrinae or the “seats of doctrine.” Such passages may be brought together to mutually interpret one another in such a way that theologians can elucidate the doctrines of the faith. Gathered together, the individual articles of the faith come together to form the body of doctrine (corpus doctrinae) of the creedal Faith.
Reading with the Church Catholic
The interpretation of individual biblical passages must occur within the framework of this overall body of doctrine. It follows that one can only accurately read and appropriate Holy Scripture when it is read alongside and in community with the catholic Church. Because a true understanding of Scripture is possible in light of the internal and external clarity of Scripture, it also follows that there is a catholicity of the Christian faith across time and space. God the Holy Spirit calls and enlightens the elect through the preaching of the Word of God, apart from any decision or preparation they might make to receive the gift of faith. Therefore, the grace of God alone ensures that the gates of hell will not prevail against the Church (Matt. 16:18). There will always be a remnant of the faithful left to witness to the true faith (1 Kgs 19:18). The Word of God is living and active and preserves the Church in every age.
Therefore, past confessions of the Word of God in the life of the Church can serve as a guide to articulating the meaning of Scripture in our present context. Traditional interpretation of the Word and the Church’s historic preaching cannot add onto or be the key factor in clarifying the Word of God. However, they can serve as a resource and a guide to those who wish to understand and proclaim Scripture. Likewise, drawing on the catholic tradition of the faith checks novel interpretations of Scripture, such as those found in both modern cults and Christian primitivist sects. If one does not have a precedent for a particular belief, or reading of Scripture, in the earlier Christian tradition, then it is likely not the correct one mandated by the Holy Spirit.
Nevertheless, theologians must recognize that the Church and its tradition are still subject to Scripture as the ultimate authority. Human teachers are subject to sin and finitude and can fail. Hence, unlike the claims of Roman Catholicism, one should not so much read Scripture under the authority of the Church as a hierarchical institution, but rather read Scripture with and alongside the catholic Church as a fellowship of faith.
From the draft manuscript for Lutheran Dogmatics: The Evangelical-Catholic Faith for an Age of Contested Truth (Lexham Press).
Cover image from Michael Bird, “Clarifying the Clarity of Scripture,” Word From The Bird, Substack, September 15, 2024, accessed June 29, 2025, https://open.substack.com/pub/michaelfbird/p/clarifying-the-clarity-of-scripture-deb?r=78kg7&utm_medium=ios. Other image from MVCCADMIN, “Scripture Alone: The Sufficiency of Scripture,” Mountain View Christian Church, October 22, 2017, accessed June 29, 2025, https://mountainviewchristian.ca/wp-content/uploads/2017/10/sola-scriptura.jpg.