In 1935, Dietrich Bonhoeffer was presented with a much-sought-after opportunity to study non-violent resistance under Gandhi in his ashram, but, perhaps remembering Barth’s rebuke, decided to return to Germany in order to head an underground seminary for training Confessing Church pastors in Finkenwalde. As the Nazi suppression of the Confessing Church intensified, Barth was driven back to Switzerland in 1935; Martin Niemöller wasarrested in July 1937; and in August 1936, Bonhoeffer’s authorization to teach at the University of Berlin was revoked after he was denounced as a “pacifist and enemy of the state” by Theodor Heckel .
Bonhoeffer’s efforts for the underground seminaries included securing necessary funds, and he found a great benefactor in Ruth von Kleist-Retzow. In times of trouble, Bonhoeffer’s former students and their wives would take refuge in von Kleist-Retzow’s Pomeranian estate, and Bonhoeffer was a frequent guest. Later he fell in love with Kleist-Retzow’s granddaughter Maria von Wedemeyer, to whom he became engaged three months before his arrest. By August 1937, Himmler decreed the education and examination of Confessing Church ministry candidates illegal. In September 1937, the Gestapo closed the seminary at Finkenwalde and by November arrested 27 pastors and former students. It was around this time that Bonhoeffer published his best-known book, The Cost of Discipleship, a study on the Sermon on the Mount, in which he not only attacked “cheap grace” as a cover for ethical laxity but also preached “costly grace”.
Bonhoeffer spent the next two years secretly travelling from one eastern German village to another to conduct “seminary on the run” supervision of his students, most of whom were working illegally in small parishes. Thevon Blumenthal family hosted the seminary in its estate of Groß Schlönwitz. The pastors of Groß Schlönwitz and neighbouring villages supported the education by employing and housing the students among whom Eberhard Bethge, who later would edit Bonhoeffer’s “Letters and Papers from Prison” as vicars in their congregations.
In 1938, the Gestapo banned Bonhoeffer from Berlin. In summer 1939 the seminary was able to move to Sigurdshof, an outlying estate Vorwerk of the von Kleist family in Wendisch Tychow. In March 1940 the Gestapo shut down the seminary there following the outbreak of World War II.