If you go to this website you can hear Barth deliver his lectures on evangelical theology in Princeton in 1962, as well as some Q and As. I especially recommend the latter, since it gives you a chance to appreciate Barth's wit and self-deprecation. One exchange in particular stands out,
In the Q and A with students, one of them quotes to Barth a sentence he wrote in The Resurrection of the Dead (from the mid 1920s), and asks Barth is he still agrees with this sentence, and if he does, is it not problematic? Barth comments that that book was written a long time ago, and that there are certainly sentences which he can no longer uphold. But he asks the student to read the quote again slowly, and says "I will look into what I can make of it." So the student repeats the quote from Resurrection: "Exactly in the place of that which makes me a man, the human soul, is placed that which makes God God."
In the recording you hear a sort of confused pause by Barth, followed by silence, and then laughter from the crowd. Barth himself seems to be laughing. As the laughter stops, Barth asks: "Can you tell me...what I may have meant...!?" Barth is laughing again by the end of his question, and the students follow suit.
From another theologian this question could come across as patronising and arrogant, as if to say: well of course I know what I meant, but I want to check to see if YOU know how to interpret me. But here it is a genuine question from Barth, a question which seems to be mocking the obscurity of the original quotation. For all Barth's giftedness as a theologian, his best characteristic is perhaps his refusal to take himself seriously. He is not precious about "his" theology. From the very beginning of Church Dogmatics he insists that dogmatics is not mastery, but service. This, sadly, is a characteristic often absent from Barthians, who would do well to pay as much attention to the spirit of Barth's theology as to the letter.
If you want to hear the exchange for yourself, click here and go to minute 10:30