Church Dogmatics. My goal is to get through the whole 14 vol. set over the next several years. Needless to say, I'll be sharing some of his gems as I come across them. Here's Barth on the importance of theological work:
"How disastrously the Church must misunderstand itself if it can imagine that theology is the business of a few theoreticians who are specially appointed for the purpose, to whom the rest, as hearty practical men, may sometimes listen with half an ear, though for their own part they boast of living 'quite untheologically' for the demands of the day ('love'). As though these practical men were not continually preaching and speaking and writing, and were not genuinely questioned as to the rightness of their activity in this regard! As though there were anything more practical than giving this question its head, which means doing the work of theology..."
"As though there could be any more urgent task for a Church under assault from without than that of consolidating itself within, which means doing theological work!"
"The whole Church must seriously want a serious theology if it is to have a serious theology."
"The freedom claimed when men think they can and should theologise 'quite untheologically' is the freedom to prattle heretically or in a way that makes for heresy. There is no room in the Church for this freedom."
Church Dogmatics I1 76-77