Last night I watched Bonhoeffer, a documentary on the German pastor who believed the presence of Christ in the world was to be found in the church, and experienced via the church's mission. I first read his Cost of Discipleship while visiting my girlfriend (now my wife) in Germany back in 1994. I have decided it's time to pick it up and read it again. I've already found encouragement and conviction within its pages this morning. For Bonhoeffer "discipleship" is not knowing a confession, or even being taught biblical truth, but is actually knowing and following Jesus. Doctrine and knowledge are of course important, but Bonhoeffer argues that discipleship is about the church being, not knowing. In Chapter One he condemns much of what passes as Christianity both in his day and ours as well.
...Christianity without discipleship is Christianity without Christ. It remains an abstract idea, a myth which has a place for the Fatherhood of God, but omits Christ as the Living Son... In such a religion there is trust in God, but no following of Christ.
(The Cost of Discipleship, pg. 59)
If you haven't read it, or if it's been a while read The Cost of Discipleship. And check out the documentary too. It's good stuff.