On "The Two Powers in Heaven" by Alan F. Segal ***

This rather technical monograph attempts to trace the concept of "two powers in heaven" within early rabbinic writings in order to find the origin of the heresy (and just what it was the rabbis were responding to: Christianity? gnosticism? paganism? something else?). Segal spends a lot of time quoting and analyzing the rabbinical texts, most of which I'm not familiar with. What this meant for me, as one who has not read the Mishnah and other such works or who has spent a lot time reading about them, was that I found Segal's book at times difficult to follow--and a little dull.

Things pick up a bit toward the end, once Segal turns to intertestamental writings, Christian writings, and gnostic writings. In part, that was because I was more familiar with them, but also he spends a lot less time on these than he does on the rabbinacal work--so he's not quite so punctilious and technical.

The basic point that Segal is able to make is that the rabbis were responding not just to ideas that were around at the time in which they were putting their sayings down but to ideas that had been around for a century or two, ideas that go back to at least the first century. Some of these ideas may have come from Hellenistic Jews such as Philo, some from Christians, and some from gnostics. He also finds that most gnostic ideas probably had a route in Judaism rather than in Christianity, though of course such ideas drew from all sorts of sources.

Segal's book is referenced in the work of a number of other scholars, so there's no doubt that it is important. But writers such as Larry Hurtado discuss a number of the same things, only in a way that is much more accessible. So unless one has an interest in the real technical side of this discussion--and specifically of the rabbinical side--it's probably not the book to start with.