Historical fact: Jesus of Nazareth founded a new religious movement. But what kind of religious movement exactly? A new religion that competed with Judaism? Yes, used to be the common Christian view, stressing the use of expressions like “New Covenant”, the polemic against the Jews that can already be found in the Gospels, and the story that Jesus appointed Peter as leader of his church. Yes, agreed the Jews, and answered the polemic with several stories in the Talmud.
Now, we’re not so certain anymore. The expression “New Covenant” can also be found in the Death Sea Scrolls, and was probably common within Judaism. The Christian polemic is, when we look more carefully, often directed against the Judaeans (Jesus was from Galilee) and specific groups. And finally, Jesus appointed Peter as leader of his ekklesia, but this word could be used to describe any Jewish community (for example in the Diaspora) or the adherents of any Jewish religious leader (the World English Bible translates “assembly”, not “church”). None of this points to Jesus as founder of a religion that competed with Judaism – or even superseded it, as Christians have often thought.
I am preparing a book in which I describe how Judaism was, at the beginning of our era, very pluriform, consisting of Sadducees, Pharisees, Essenes, the sect that appears to be responsible for (parts of) the Dead Sea Scrolls, the movements of men like John the Baptist, Jesus, Bannus, and Theudas. This pluriformity came to an end when the Temple was destroyed, a disaster that only the Pharisees and the followers of Jesus could cope with: the first, because they had a network of teachers; the second, because salvation was possible through faith in Jesus, the Temple being of only secondary importance.
In this way, Roman imperialism was the cause of the rift between the two remaining types of Judaism, one of them still called Judaism, the other now known as Christianity. Both claimed -and usually still claim- to be the only continuation of Temple Judaism. Often, they have chosen diametrically opposed positions in the theological debates of the late first and early second century: e.g., when the Christians opened their ranks to pagans, the rabbis decreed that one could only be Jewish when one had a Jewish mother. And because rabbinical Judaism could claim the title of rabbi, the Christians -who worshipped someone who had also been called a rabbi- gave the leadership to priests, which is odd because there was no temple left.
These examples show that the two branches were still communicating – after all, you need to communicate if you chose opposite positions. But there must have been a more friendly dialog, and I think that the teachings about Good Works that are attributed to Yohanan ben Zakkai (‘Avot de rabbi Nathan 4.5) and are mentioned in the Epistle of James 2.14, may be examples of this. As I see it, this dialog continued as long as there were Jewish Christians, which appears to have been the case until the revolt of Bar Kochba.