Hengel was an early and profound influence on me. In my early years of NT study, when historical study raised questions that seemed (wrongly as it turned out) to threaten faith, his work on the early church and christology showed me that the one might actually shed light on the other. In a weird way, and in contrast to the usual throwaway perceptions about the kind of teutonic scholarship that Hengel's work epitomized, I found the density of his work unbelievably exciting. I pored over those foonotes, chased down some of the references, wondered why he seemd to get so cross with F. C. Baur. I used to put the books down (and mention here should be made of SCM Press under John Bowden who issued English translations - a ministry that, alas, has fallen by the wayside) thinking "How can anyone know that much?!" a thought quickly followed by "I want to know that much!". Hengel for me at that time was a giant, whose work provided my orientation to the Judaism of Jesus' world (I read him before I read Sanders) and who showed me ways in which my unreflective evangelical convictions about Jesus might in some way be a legitimate expression of aspects of the biblical witness that he so carefully traced. Anyone who wants to really get a grip on the whole notion of the foolishness of Christian proclamation could do a lot worse than read Crucifixion.
As time has gone on, I read him less. My own views changed, not least on the relation of history to faith. The work on John was ingenious, but the question of who wrote the gospel was, by the 3rd year of my undergraduate studies, the least interesting question. I continued to buy the books on Paul especially, but they sometimes seemed to lack the thrilling quality of the earlier work (co-authorship became more common for Hengel). But on my shelves I keep with pride my copies of Judaism and Hellenism (the wonderful 2 volume hardback: Volume 1 = 314 pages of text; Volume 2 = 335 pages of notes, bibliography and indices - how wonderful), The Zealots, and those SCM paperback compilations that I picked up for £5 in the SCM sale: The Cross of the Son of God; Between Jesus and Paul; Acts and the History of Earliest Christianity. Last year I had the privilege of reviewing Volume IV of his laughably titled Kleine Schriften which reconnected me with much of this earlier work, but now in his native tongue. That reminds me to mention that his other great legacy will be the WUNT series in which so much of his own recent work was published, but which has done so much to preserve a tradition of scholarship that, with all its weaknesses, nevertheless shapes our discipline and keeps me humble whenever I begin to think that I know anything.
Tübingen has lost a great Neutestamentler. If God writes footnotes, then at least Hengel will be on hand to add a judicious classical reference or two, probably from memory. Requiescat in pacem.