In popular Christian lingo, we commonly say something along the lines of, "Paul's ministry among the gentiles converted pagans to Christianity directly without requiring them to first become Jews." This type of thinking about Paul is common and also affects contemporary reading of other NT texts (e.g., Acts 10–11). At its heart, of course, is the assumption (which goes largely ignored, if not unnoticed) that to become a Christian is not to become a Jew.
But is this how the labels would have been understood in a first-century context? If we were average, everyday, nameless gentiles going about our business in the agorai of any major city of the Mediterranean and someone in our family forsook the family devotion to Apollo or Artemis or any of the other gods to worship Israel's God and his crucified prophet, Jesus, would we understand this development as anything other than a conversion to Judaism? And if not (and I'm not assuming a negative answer, except perhaps for the sake of argument), is this because we, as outsiders, have an insufficient understanding of the relation between Christianity and Judaism? In other words, would Paul, or Peter, or the average Christian, have seen a gentile's conversion to Christianity as not being a conversion to (a form of) Judaism?
At the moment I'm reviewing Not God's People: Insiders and Outsiders in the Biblical World, by Lawrence M. Wills. His discussion of "Jew and Gentile as Other in Paul" provides a helpful discussion of a number of issues regarding the construction of the We and the Other, though the book as a whole suffers some important weaknesses. But he makes one particular comment that stood out to me for being fairly standard within New Testament scholarship and yet perhaps in serious need of rethinking. Wills says,
Immediately before and after Paul's formula of "neither Jew nor Greek" (Gal 3:28) it is emphasized that those who have been baptized into Christ are now children of God and children of Abraham. Paul, and other writers of the early church, quickly developed new language of being children of God, an extended kinship group. All ethnicity in the ancient world was understood as genealogy, and Paul bestows a new family tree on the converted gentiles. (2008: 187; my emphasis)
My problem: I realize that it won't do for us to ignore any differences between Christianity and Judaism in the first century; clearly there were differences between Jesus, Paul, and other characters in first-century Christian narratives and other Jewish figures with whom the former came into conflict. But how do we justify to ourselves and our readers the assertion that the family tree onto which gentile converts to Christianity were grafted (to echo both Wills and Paul) was new and not Jewish? How can Wills (or other NT scholars, for that matter) recognize Paul's appeal to Abraham (!) as a patriarch of the heirs of the promise and yet ignore the clearly Jewish markers delimiting Jesus' followers from others dotting the social landscape?
As a tentative hypothesis, then, I would like to test the formulation: In the first century CE (and so throughout the texts comprising the New Testament), to become a follower of Jesus was to convert to an expression of Second-Temple era Judaism (even toward the end of the century after the Temple was destroyed). I would understand the dynamics of these labels as analogous to the dynamics that would have obtained if a gentile resident of the Decapolis became an Essene and took up residence at Qumran. Clearly there are differences between Essenism and Christianity, but those differences do not amount to the former being an expression of Judaism and the latter something else altogether. Gentiles-become-Christians were gentiles-become-Jews, though other Jews (some of whom considered themselves devotees of Jesus) would have engaged Paul critically on the question of the terms of this "becoming."
What say you?