Contesting Conversion: Genealogy, Circumcision, and Identity in Ancient Judaism and Christianity by Matthew Thiessen (review)

There are certain tensions that I believe to be existential in Judaism. That is to say, Jews and Jewish groups must map out their beliefs and practices to fit somewhere on the continuum between the opposing poles concerning these issues. For instance, there is a tension in Judaism between t’fillat keva (fixed prayer) and kavvanah (intention). There is a tension between a focus on talmud torah as of primary importance and a focus on righteous and pious action. Matthew Thiessen’s book focuses on perhaps the greatest tension of all in Judaism, one that has accompanied it from its very outset: the tension between Judaism as a genealogically defined ethnicity and Judaism as an open, universal religion. Throughout Jewish history there has never existed a group that has not, in one way or another, been forced to provide some answer to the question posed at the beginning of this book: can one who is born a Gentile become a Jew?

This question is so essential and determinative of a group’s identity that nearly any book addressing the topic is bound to be of interest. And Thiessen’s book is indeed interesting, well-written, and enjoyable. Indeed, its only real problems are that it occasionally restates conclusions that have been well-known to scholars for some time and that it tends to focus on marginalized groups as if they are representative. Nevertheless, despite these issues, I do think there is much to be gained from Thiessen’s readings of often ignored texts and his innovative readings of at least one text.

The first section of the book surveys the Hebrew Bible, demonstrating that “conversion” was simply not possible in the biblical period. Thiessen focuses extensively on the story of the circumcision of Ishmael and Isaac, claiming that for the author of the story, only eighth-day circumcision is effective as a sign of the covenant. This explains why Isaac’s seed is part of the eventual covenant with God, whereas Ishmael’s is not. Thiessen also surveys other passages concerning circumcision in the Bible, noting that even when Gentiles are circumcised, this circumcision—because it is not performed on the eighth day—does not cause the Gentile to enter the Israelite covenant. This section is interesting and convincing but not particularly innovative. As Thiessen notes, Solomon Zeitlin said the same thing nearly eighty years ago, and Shaye Cohen has reiterated it more recently. Thiessen puzzlingly fails to address the fact that the Book of Ruth (and probably other biblical books as well) present permeable boundaries between Israelite men and non-Israelite women. Thiessen focuses so narrowly on circumcision that he neglects to discuss the possibility of women joining the covenant through marriage with Israelite men.

In the second section of the book Thiessen turns his attention to Second Temple groups. Here he frequently notes his disagreement with Shaye Cohen, who once wrote (in his essay, “Conversion to Judaism in Historial Perspective: From Biblical Israel to Post-biblical Judaism,” published in Conservative Judaism 36:4 [Summer 1983], p. 42) that “by the time of the Maccabees, conversion, ritually defined as circumcision, is securely in place, not to be questioned until the Middle Ages.” Thiessen identifies some groups who would not have agreed that circumcision could overcome the genealogical boundary between Gentile and Jew. Most of these chapters deal with three pieces of evidence for such groups among Jews: the Book of Jubilees (and Jews who accepted the work as authoritative); the Jews who opposed the Herodian dynasty due to Herod’s Idumean ancestry; and the “Animal Apocalypse,” preserved in 1 Enoch 85–90. The evidence from Jubilees is solid, but here Thiessen merely confirms what Christine Hayes already wrote in her book on Gentile Impurity. (Hayes’ book, Gentile Impurities and Jewish Identities: Intermarriage and Conversion from the Bible to the Talmud, was published in the U.S. by Oxford University Press in 2002.) The evidence of opposition...