Bonhoeffer’s resistance to the Nazi regime included his support for and pastoral participation in the Confessing Church along with other prominent Protestant theologians like Karl Barth and Martin Niemöller, as well as his intricate association with the broader ecumenical movement. When the effectiveness of the Confessing Church’s opposition to Hitler was blunted and his efforts to bring the moral authority of the ecumenical movement to bear failed, Bonhoeffer became involved with the so-called Abwehr conspiracy, which intended to assassinate Hitler, overthrow the Nazi regime, and end the war.
After imprisonment for his role in the escape of Jews to Switzerland, Bonhoeffer was implicated in the failed assassination attempt of July 20, 1944. At the age of thirty-nine, he was hanged by the S.S. at the Flossenbürg concentration camp on April 9, 1945, just weeks before the liberation of the area under Allied troops. Dietrich Bonhoeffer’s life and death are a testament to his commitment to the Christian faith and his ardent opposition to the absolutism and idolatry of Nazi Germany.
I also recommend checking out the new biography by Eric Metaxas, Bonhoeffer: Pastor, Martyr, Prophet, Spy. You can read my review of Metaxas’ book here.
The single best work of Bonhoeffer’s to familiarize yourself with his life and thought is the little classic, Life Together.