Barth said that it was impossible to do theology at all unless you started from the assumption that God, in fact, exists. In early 20th century Germany, this was a controversial assertion.
Equally interesting to me was the story of Bonhoeffer’s family religion. He had been raised in a family that had strong connections to the Moravian traditions founded by Count Zinzendorf, who John Wesley both learned from and later rejected.
The United Methodists declared Bonhoeffer a martyr in 2008. Although I always saw the affinities between Wesley and Bonhoeffer by reading their works, I did not know Count Zinzendorf had influence on both of them.