I have a number of set pieces that I use when I speak on U2 to Christian groups, and one of them involves running quickly through an escalatingly complex list of Biblical allusions in their work. One of the most common questions I get in response is "How do they get away with this?" While I often laugh and say I don't know (and there is some truth in that), a new article by Deane Galbraith (whose work will also be represented in the anthology of papers from the first U2 conference) in the scholarly journal Biblical Interpretation has a fuller answer.
Entitled "Drawing Our Fish in the Sand: Secret Biblical Allusions in the Music of U2," ("secret" is a bit of a technical term here) the article shows how U2 "construct two different, perhaps even irreconcilable, groups of listeners" through the use of subtle, ambiguous allusions to Scripture which create a climate where "Christian references are hidden from mainstream listeners and media while being readily recognizable to their Christian fans." The initial part of the article documents U2's deliberate choice to keep their Christianity largely covert and difficult to pin down (a posture which has relaxed dramatically after Bono's engagement with American evangelicalism through DATA, but which anyone who was a fan in the 80s and 90s will remember vividly!), drawing on interviews and on some heretofore little-cited material from the presentation Bono, Edge and Larry gave to Christian artists at a Ghettout event in 1981.
Galbraith continues with a treatment of different kinds of allusions ("a figure which invites a knowledgeable reader to depart from her linear progression through the alluding text, by providing a marker to one or more evoked texts... in a manner which guides but does not wholly specify the relevant relationships between the texts" - note that this is substantially more complex than just "Bono's quoting the Bible"). The paper then concludes with some very interesting examples contrasting readings of particular songs by Biblically-literate versus non-Biblically-literate listeners (e.g. "Sunday Bloody Sunday," "Until the End of the World," "I'll Go Crazy If...," and perhaps most entertainingly "Breathe." FYI, if you've shared your opinion about NLOTH Bible allusions on a fan forum, your post just may be cited!)
Since Brill publishes this journal, the article will cost you an arm and a leg if you can't find a nearby university or seminary that has a subscription, but it's worth a read even if you think you know a lot about the topic already. I think it is important to keep in mind Galbraith's overall point, that what we have in U2 is not lyrics that are quite obviously explicitly Christian and a lot of people don't get, but lyrics that consistently, quite deliberately leave possibilities open to invite more than one reading.