Theology is fundamentally about knowing and confessing the Triune God through faith in his Word (Rom. 10:9). God the Holy Spirit works to create saving faith through the Word. Such faith is in no way the byproduct of human will or activity (Rom. 10:17, 1 Cor. 2:14-16). Scripture does allow that a natural knowledge of God accessible to all people exists (Ps. 19, Rom. 1-2). Yet, this philosophical recognition of God and his reality is not theology in its proper sense. At best, the natural knowledge of God is a partial, garbled knowledge that the sinful human heart will manipulate according to its own purposes. Since God saves by faith through grace alone, so too the theology that gives rise to that faith comes by grace alone.
In this vein, the early Lutheran theologian Johann Gerhard (1582 – 1637) spoke of theology as a “practical habitus” that God implanted in the human heart and mind. In the Aristotelian philosophy of the day, a “habitus” was an aptitude for developing a habitual behavior, such as a virtue. Gerhard argued that God’s grace made theology possible by means of the Holy Spirit working on the heart and mind of the theologian. This divine action enables readers to fully apprehend the truths present in the text of Scripture. Of course, the theologian might still draw on his own humanly acquired knowledge when studying Scripture. However, only God’s Spirit and the gifts that he bestows allows the theologian to properly apprehend the content and unity of the Faith. Such a divinely given “aptitude” is “practical” because its ultimate end is the proclamation of the grace of God in Christ through Word and Sacrament.
From the draft manuscript for Lutheran Dogmatics: The Evangelical-Catholic Faith for an Age of Contested Truth (Lexham Press).
Cover image from: Tom Nash, “What Are Inspirations of the Holy Spirit?,” Catholic Answers, accessed June 23, 2025, https://www.catholic.com/qa/what-are-inspirations-of-the-holy-spirit; other image from Chantal LaFortune, “Sacred Scripture Unveiled,” Holy Apostles College & Seminary, December 8, 2023, accessed June 23, 2025, https://holyapostles.edu/sacred-scripture-unveiled/.