Bonhoeffer, born a Pole, [biography] was one of the most influential Christian leaders in Nazi Germany and one of the few German-Christian leaders who opposed the Nazis in the 1930s. The Church for various reasons, either supported the Nazis, was indifferent, or offered uneven and disunited opposition.  Even so, the Christian churches did rescue, in-toto some 1 million Jews and countless Catholics.  The Nazis were evolutionists and biological racists.  Evolution was their iron law, German Aryans and a racially superior Germany, their god.  That is why they destroyed both the Lutheran and Catholic churches.  Christianity opposed everything the Nazis stood for.  

Bonhoeffer was one of the few Christian ministers who warned the world about the Nazis. His 1933 essay “The Church and the Jewish question” was prescient, foretelling much of the coming brutality the Nazis would direct against both Jews and Christians. Bonhoeffer knew the Nazis would attempt to wipe out not only Judaism, but its offspring, Christianity.

By the mid 1930s, the Nazis had developed a 30 point plan to replace the Christian church with a Reich's church.  During the 30s all Christian books, pamphlets and newsletters were shuttered.  Starting in 1936 the Lutheran church was taken over by the SS, and the Gestapo bullied the Catholic church - usually through murdering its leaders - to spew Nazi drivel.  By 1942 the bible was replaced with Mein Kampf in all Catholic and Lutheran churches. As well, all Catholic statuary and imagery was taken down and replaced with pictures of Hitler and a sword. The Church was gutted and during the war some 5 million Catholics were gassed.  

So much for godless unscientific Darwinism.

Bonhoeffer's courage – he was hung in 1945 for his virulent anti-Nazism – and his Christian belief which permeated his actions is amply elucidated by Marsh in his new biographical work on Bonhoeffer. The WSJ reviewer states:

“"The Cost of Discipleship" (1937), [written by Bonhoeffer] which is both bracing and haunting to read in light of the events that followed. ("Just as Christ is Christ only in virtue of his suffering and rejection, so the disciple is a disciple only insofar as he shares his Lord's suffering and rejection and crucifixion.") Faith, Bonhoeffer stressed, could be found only in actions of faith: "Only he who obeys, believes."

Just about the entire German church, Catholics and Protestants, turned up its belly to Hitler —and was gutted. Bonhoeffer was undeceived from the start. Within two days of Hitler's ascension in 1933, with storm troopers already in the streets, Bonhoeffer gave a dangerous radio address in which he proclaimed resistance to the Reich and support for the Jews. His sense of Christian responsibility and fraternity would only grow firmer. "Only he who cries out for the Jews may sing the Gregorian chant," he said in 1938.

Eventually this gentle, cerebral man became a quite capable double agent, ostensibly working for German military intelligence while he was actually passing information to the nations at war with Germany, as well as helping Jews escape. The pacifist so adamant that at one time he believed all violence was demonic joined a group that launched multiple assassination attempts on the life of Hitler. "Both the no and the yes involve guilt," Bonhoeffer told one of his anguished co-conspirators. The only consolation lay in knowing that the guilt was "always borne by Christ."

WSJ Review

Bonhoeffer was a Christian martyr who died defending the defenceless against Darwinian racial fascism.