Barth explains his objections to exegesis that never moves beyond the historical-critical level [for context see previous two posts]:
Taking Jülcher’s work as typical of much modern exegesis, we observe how closely he keeps to the mere deciphering of words as though they were runes. But, when all is done, they still remain largely unintelligible. How quick he is without any real struggling with the raw material of the Epistle, to dismiss this or that difficult passage as simply a peculiar doctrine or opinion of Paul! How quick he is to treat a matter as explained, when it is said to belong to the religious thought, feeling, experience, conscience, or conviction,—of Paul! And, when this does not at once fit, or is manifestly impossible, how easily he leaps, like some bold William Tell, right out of the Pauline boat, and rescues himself by attributing what Paul has said, to his ‘personality’, to the experience on the road to Damascus (an episode which seems capable of providing at any moment an explanation of every impossibility), to later Judaism, to Hellenism, or, in fact, to any exegetical semi-divinity of the ancient world!
Karl Barth, The Epistle to the Romans, trans. Edwyn C. Hoskyns (New York: Oxford University Press, 1968), 7f.