The Abwehr was the intelligence arm of the German army prior to and during World War II, and in which Bonhoeffer served as an operative, covertly participating in the conspiracy to assassinate Hitler and remove the Nazis from power. Since the Abwehr was an already-existing part of the German military establishment, it was able to maintain some institutional independence from direct Nazi oversight, unlike the paramilitary and intelligence units directly tied to the Nazi party, like the Gestapo, the SS, and the SA. As an Abwehr agent, Bonhoeffer was able to fulfill his obligatory military duty and ostensibly serve the German war aims, while secretly joining with the conspirators against Hitler, most of whom were high-ranking members of the German army establishment.

A significant focus of Bonhoeffer’s theological work was the question, “What is the church?” This appeared both in his doctoral thesis work and his later experiments in communal Christian living in the seminary program at Zingst and Finkenwalde. Rather than identifying the church with any single institution, organization, or denomination, Bonhoeffer believed it was revealed in the shared life of any group of believers who were committed to living out the faith of Jesus as expressed in the Bible.