this book begins by discussing the so-called "German Christian" movement in Nazi Germany. Famously, this group (Ludwig Müller, Walter Grundmann, Emmanuel Hirsch et al.) attempted to dejudaize Christianity with an eye toward dejudaizing Europe. They argued that Jesus led his followers out of the shackles of Jewish legalism. Over and against this program, Rudolf Bultmann argued that Jesus remained a Jew his whole life and did not lead any sort of exodus away from Judaism. Rather Jesus critiqued a particular form of legalism (for more on Bultmann see here).
While Theissen disagrees with Bultmann's neat distinction between "law" and "legalism", he commends Bultmann for offering an alternative to the anti-Semitic theology of his context and for locating Jesus within Judaism. After setting the stage in this way, Theissen observes:
I would further problematize this by adding that Christians have tended to paint Jesus as a Jew like Paul (and/or James). Michael Cook has recently argued that Jewish scholars have tended to paint Jesus with broad brushstrokes borrowed from rabbinic training. Scholars who are disenchanted with religion in general have tended to portray Jesus as a philosopher / socio-political commentator. Please note that I am using qualitative language here. There are notable exceptions to all of these general tendencies. I should also say that I am not repeating the adage that we tend to see Jesus in our own reflections. This is probably true, but it would be more true to say that we tend to find a certain "type" of Jew in our research and then associate Jesus with this type.
It gets even more problematic. Most students of Jewish and Christian Scripture have developed canons within canons of the Old Testament and Hebrew Bible. We have constructed "types" of Israel drawn from particular texts. For example, many Christians claim that "true Israel" acted as a light to the nations. Here we draw from a few texts that serve as hermeneutical lenses. Or we belittle "faithless Israel" for forgetting the covenants so quickly and often. The problems with such stances should be obvious, but I will risk being obvious: We construct particular types of Israel to find spiritual space for our own interests within our sacred texts - often to the detriment of others.
When we Christians project these "types of Israel" onto the New Testament, we end up locating Jesus in the religious space that we've constructed for ourselves as "true Israel". Conversely, we end up locating "the Jews" or "the religious leaders" of Judaism (as portrayed in the NT) within our construction of "faithless Israel". Or - and I see this quite often - we use the same types in reverse. We Christians identify more with "faithless Israel" or we identify as "the religious establishment". In this case, we project the role of judge onto Jesus so that he can chastise us sinners for not being more like "true Israel" (for what it's worth, this latter point tends to be neglected in the Jewish-Christian dialogue I've participated in and witnessed).
Here is my point: there are literally dozens of portraits of "Israel" in the Hebrew Bible. And for every portrait of Israel we find, we can find a equally viable portrait of Jesus in contemporary scholarship: Jesus the new Adam, Jesus the new Earth-keeper/former, Jesus the leader of new exodus, Jesus the legal critic, Jesus the idol-smasher, Jesus the judge, Jesus the king, Jesus the wisdom teacher, Jesus as Wisdom, Jesus the prophet, Jesus the apocalyptic prophet, Jesus the story-teller, Jesus the political commentator, Jesus the revolutionary, Jesus the quasi-nihilist. Add to this all of the "types" of Jews that we find in second/post-Temple Judaism(s): Jesus the aggrandized artisan, Jesus the miracle worker, Jesus the exorcist, Jesus the Hillel-like rabbi, Jesus the purifier, Jesus the diaspora Jew who is fluent in Plato and Homer, Jesus the ascetic, Jesus the second person of the Trinity. And we could add dozens more portraits by creating combinations of these categories.
All of the above are "Jewish portraits" of Jesus. Now, some of these are more plausibly applied to Jesus, but none of these is any "more Jewish" than the alternatives. None of these types are only "marginally" Jewish. So what does it mean to say that Jesus was Jewish? Theissen's chapter suggests a really intriguing way forward. I'll discuss this more in part two.
Parts 2 and 3 can be found here and here.