Dietrich Bonhoeffer's Essential Question

I've been reading "7 Men and the Secret of Their Greatness" by Eric  Metaxas and I noted in his treatment of Dietrich Bonhoeffer that Bonhoeffer pondered for years the question, "What is the church?".  This led him to write several books on the subject of Christian community, but more importantly make choices about his own actions that led him to fight the Nazi regime openly and subversively.  These actions eventually led to his imprisonment and hanging at the order of Hitler.  I was impressed by the fact that it was in seeking an answer to this question, that Dietrich Bonhoeffer came to clear conclusions about the proper role of Christianity in life, which underscores the power of a well crafted question and continuous and focused attention to its answer.