"You can deduce from the very way in which I address you that I do not regard your departure for England as anything but a necessary personal interlude. Once you had this thing on your mind, you were quite right not to ask for my wise counsel first. I would have advised you against it absolutely, and probably by bringing up my heaviest artillery. And now, as you are mentioning the matter to me after the fact, I can honestly not tell you anything but 'Hurry back to your post in Berlin!' . . . With your splendid theological armor and your upright German figure, should you not perhaps be almost a little ashamed at a man like Heinrich Vogel, who, wizened and worked up as he is, is just always there, waving his arms like a windmill and shouting 'Confession! Confession!' in his own way—in power or in weakness, that doesn't matter so much—actually giving his testimony? . . . Be glad that I do not have you here in person, for I would let go at you urgently in quite a different way, with the demand that you must now let go of all these intellectual flourishes and special considerations, however interesting they may be, and think of only one thing—that you are a German, that the house of your church is on fire, that you know enough and can say what you know well enough to be able to help, and that you must return to your post by the next ship. . . ."
Karl Barth to Dietrich Bonhoeffer, 20 November 1933, as quoted (but with the substitution of "now" (jetzt) for "not") by Eric Metaxas, in Bonhoeffer: pastor, martyr, prophet, spy (Nashville, TN: Thomas Nelson, 2010), 197-198, where DBWorks 13 (London: 1933-1935), trans. Isabel Best (2007), 39-41, is cited.
Until I can check DBWerke 13, here is the German as quoted on p. 158n275 of Wie Schafe mitten unter die Wölfe: Die Bekennende Kirche in Ostpreußen und Dietrich Bonhoeffers Visitationsreisen 1940 (2012), by Ulrich Schoenborn: