Today marks Dietrich Bonhoeffer's birthday. Therefore, in honor of his legacy of "costly discipleship" we've posted below an introduction to his life and thought by Tom Greggs, Professor of Historical and Doctrinal Theology at the University of Aberdeen. If for some reason you don't know much about Bonhoeffer and this video piques your interest, then be sure to read Eric Metaxas's biography of him (here). Enjoy...