In the winter semester of 1920/21 at the University of Freiburg, Heidegger delivered a lecture titled "Introduction to the Phenomenology of Religion." Although the original lecture manuscript is lost, five sets of notes from students (Oskar Becker, Helene Weiß, Franz-Josef Brecht, and others) have allowed for a partial reconstruction of the lecture. The notes reveal that Heidegger's lecture can be divided into two distinct parts, separated by a hiatus on November 30, 1920, due to unspecified objections. Oskar Becker's notes, in particular, indicate the interruption and the shift from a "Methodical Introduction" to a "Phenomenological Explication of Concrete Religious Phenomena."
This work is largely Exegetical as he examines Biblical passages utilizing a range of texts, utilizing a range of translations and tracing the slight differences including Erasmus' Novum Testamentum Graece cum apparatu critico ex editionibus et libris used by Melanchthon. Heidegger uses his distinctive phenomenological methodology to deconstruct religious experience, analyzing its fundamental elements and its significance for human existence. He ventures beyond traditional theological inquiry, integrating phenomenological, psychological, and historical dimensions to explore the nature of religion. Heidegger's approach is not a cataloguing of religious beliefs or practices, but rather an in-depth examination of the nature of religious experience, its impact on human consciousness, and its existential significance. This work is emblematic of Heidegger's broader philosophical project, which seeks to understand the fundamental nature of Being, Dasein, and Existence through the examination of various human experiences, including religion. The influence of Kierkegaard is palpable in this work in his rejection of the Positivist English Empiricist line of thought.