In this lecture, Prof. Zaborowski turns to Heidegger's religious origins and shows the extent to which his study of theology and his Christian faith shaped his entire way of thinking. It briefly traces key moments of his early religious formation and then discusses the extent to which Heidegger's way of thinking can be understood against this background. In addition to his early Catholic phase, various phases can be distinguished in which Heidegger searched for God in different ways: the period 1) of the early Freiburg lectures, 2) of Being Time, 3) of the Contributions to Philosophy and 4) of his late work. If Heidegger's thinking can be described as the "art of living" in its performative character, it becomes clear that this is also due to this religious formation and its importance for his understanding and implementation of philosophy.