During what I call my younger "seminarian days" when as a teen and young adult I was studying as much theology and philosophy as possible in order to substantiate my person and belief system...one of the most impressive contemporary figures of Christian religious thought I read was Dietrich Bonheoffer.
Bonhoeffer was a German Lutheran pastor and theologian whose writings and beliefs significantly influenced modern ecumenical movements and thinking of Christianity and religion from a universal versus denominational standpoint. I read his book "The Cost of Discipleship" and a couple other smaller works...and came away sensing that traditional Christianity and religion is meaningless compared to the intensity, integrity and ultimate sacrifice this man made based on his beliefs. While many of his presuppositions are not mine, I do see his brand of religion and social justice as one of the strongest replications of Jesus own life and message to contemporary society. This man strove to unite and promote Christiandom...not by watering down its principles or demands...but by integrating and uniting through the core values of right living...basically "practicing what you preach".
The biggest challenge to true religion today is this call to actionable, socially responsible actions not based on hate, new revelations or piety...but based on core teachings of the historic Jesus , most of which Judaism or Islam have no qualms with.
While the outside view of comparative religions is that they are mutually exclusive, Bonhoeffer was able to mingle, debate, listen and learn about other religions, sects and viewpoints against which he would continually challenge and even shape his own views and positions. The sense of reading him is that while very mentally disciplined and stubborn (perhaps a German trait similar to those of us from Norwegian genes?), he was able to be objective without shifting with every wind of popular religious sentiment. And when it came down to challenging the standard religions and churches in his day...not that long ago...his convictions and integrity ended up costing him his life against the Nazi regime.
The actions and beliefs of Bonhoeffer that I relate or aspire to most are:
His respect for and ultimate life sacrifice for the sake of the Jewish race and religion in the middle of Nazi Germany. This took real guts.
While in Harlem and the USA he opened up to and found respect for Black Christian churches and the "experiential", emotional side of their faith which must have been a big leap for such an intellect and emotionally reserved German Lutheran.
While most of the German Christian churches...whether Catholic, Protestant, Lutheran or otherwise...flexed and did not resist the Nazis and Fascism, Bonhoeffer was strong and consistent from beginning to end in denouncing the evil of that era in his country. And while he could have rode it out in the safety of America based on his connections, he chose to go back and fight for his principles with his people knowing what he was risking.
He revived the idea of "imitation of Christ" as the principle to guide "Christian" conduct. It wasn't about just being a good person, going to church on Sundays and playing a pious role in church and society. His was no "prosperity doctrine" of love Jesus and get rich. He believed in relating to and helping the poor and less fortunate and "sharing the sufferings of God at the hands of a godless world".
He allowed his theology and thinking to change as he was confronted with new experiences or evidence that challenged him to do so. He was then able to articulate his positions and reasonings very effectively.
I would probably be inclined to go to church again on a regular basis if I were able to sit under a sharp mind and strong character of someone like Bonhoeffer. I think his charisma and ideals are strongly missing in a day when popular Christian media can do no better than Pat Robertson, Jimmy Swaggert and other Fundamental Christian extremists who continue to shape God in the image of their own imaginations and irrationality that to me is not "God-like" or in the spirit of what it truly means to be "Christian".
If you want to be challenged to live according to your beliefs and principles...you could do worse than read his abridged biography here on wikipedia...or better yet read some of his books. You don't have to agree with all Dietrich Bonhoeffer's beliefs to gain insight into the principles of what it takes in my opinion to be a TRUE believer...whatever that may mean to YOU.