James 1:1 indicates that he is writing to “the twelve tribes in the Dispersion.” Assuming that this line is to be read literally, we need to understand what a Jewish writer would have meant when he said “twelve tribes” and Dispersion. Simply put, a Jew living in the diaspora was a Jew living outside of the land. But things are a bit more complicated than that.
The Judaism of the first century developed the way it did because of the exile. This is the single event which shaped the religion primarily because it stripped the Jews of all things which constituted ethnicity. They no longer had land, their language began to shift from Hebrew to Aramaic, and there was a significant threat from intermarriage. The Jews, as a people, were at risk of losing their ethnicity.
How did the Jews survive the exile? All other peoples of the ancient world integrated and disappeared from history (for example, how many people claim to be Moabites these days?) The primary factor is Jewish Religious Tradition. This was a powerful force, based on scripture, which kept them from assimilating into a host culture. Centers of Jewish cultures developed in Alexandria, Elephantine, Babylon, etc. and continued to develop well into the current era. It is likely that Babylon and Alexandria were superior centers of Judaism to Jerusalem for much of the Second Temple period.
Those who chose to live outside of the land rather than return to Jerusalem always face problems in living in accordance with their traditional customs. The main three which are typically identified: monotheism, Sabbath, circumcision, and dietary laws. It is not a surprise to find these as the main points of controversy in the New Testament. While Paul does not shift on monotheism, he does not require gentiles to conform to the other three boundary markers and it is at least possible he may have been open to Jews not practicing food laws or worshiping on a day other than Sabbath.
The important thing to remember when thinking about the Diaspora is that it was not as much geographical as cultural. Paul might encounter strongly traditional Jews in Ephesus or Rome, and relatively “liberal” Jews in Jerusalem. In fact, I suggest that the Jews who ran the Temple in the first century were far less traditional than the Jews who worshiped in the Greek-speaking synagogues in and around Jerusalem. The first violent persecution grew out of the Greek-speaking synagogue (Acts 7).
So back to James. I think that he is certainly writing to Jews who are Christians, but they are people who may very well represent the more conservative form of Judaism before accepting Jesus as Lord. If this is true, it may explain James’ insistence on good works, for example, as a sign of true faith. To what extent does James’ letter actually reflect diaspora thinking?