Here’s a set of Barth bookmarks (pdf) that display a quotation which captures the joy and the humility with which Barth approached his theological vocation:
The angels laugh at old Karl. They laugh at him because he tries to grasp the truth about God in a book of Dogmatics. They laugh at the fact that volume follows volume and each is thicker than the previous one. As they laugh, they say to one another, “Look! Here he comes now with his little pushcart full of volumes of the Dogmatics! —and they laugh about the men who write so much about Karl Barth instead of writing about the things he is trying to write about. Truly, the angels laugh.
Barth, quoted in George Casalis, Portrait of Karl Barth (New York, 1963), 3.