The quote comes from the section in which he describes the importance of lectio continua - the consecutive reading of Scripture. For me such reading arises out of the prayer of the Daily Office, generally a solitary action. According to Bonhoeffer what is done alone comes to its most productive through what is done in community. I've been wondering how that could be translated into the digital age.
In preparing a sermon I always begin with the Bibilical passage and what issues or questions it suggests to me. I scribble down as many as I can without any prior research or any attempt at ordering or prioritizing (that comes later). I'm conscious, however, that I don't do any of that in consecutive Scriptural reading. Perhaps if I did, my reading wouldn't feel so rushed and peremptory. Bonhoeffer taught that such reading should not serve a purpose but should be for its own sake entirely. I recognize the value of the warning but perhaps he would allow me a slight adaption of a purposeful methodology. As an experiment, I'm going to tweet a thought or question out of my daily reading. They'll aim to be 'instant thoughts' - one believer's attempt to frame something that can mindfully stay with me through the day. Anyone out there willing to join to me?