The recent Jew and Judean Forum at Marginalia Review of Books is worth careful consideration for anyone interested in ancient Judaism and Christian Origins. Also, thanks to the editor Timothy Michael Law, you can read the posts here or download them in handy ebook format or pdf.

I found the two paragraphs below by Annette Yoshiko Reed in her contribution “Ioudaios before and after ‘Religion'” particularly helpful.

The focus on word-level translation reflects a longstanding tendency in Biblical Studies to treat the etymologies and histories of specific words as direct windows onto ancient thought — with the first known occurrence of a word in writing too often conflated with the birth of a concept. [See Malcolm Lowe’s essay in the forum.] If such approaches feel natural, even despite their bizarre atomization of language, it is in part because modern scholars of ancient ioudaioi have long delighted in quests for the “origins” or “invention” of concepts now common in the West. Teleology, of course, makes for poor history, and presentism courts anachronism. Yet their enduring power may help to explain the appeal of reducing the meaning of ioudaios to a question of when. To assert a moment before which a word bore a now-familiar meaning, after all, is also to evoke the point after which we might confidently presume what it means to us today.

For the limits of such approaches, we need look no further than to the use of the English term “Jew.” Those who prefer to translate first-century uses of ioudaios as “Judean” argue that “Jew” is a religious affiliation and therefore anachronistic prior to the Christian invention of “religion” in the third or fourth centuries. But this line of reasoning, as Reinhartz notes, presumes that “Jew” denotes a religious affiliation for “us” — an assumption not all English speakers who self-identify as Jews today share, as 2013 Pew polls made dramatically clear. The persistence of multiple meanings can be seen even in the scholarly debate about ioudaioi. If anything, the debate demonstrates how the term “Jew” can seem self-evidently religious to some people from the very same time and culture (and even the same profession and similar education) as others who understand it as self-evidently ethnic, political, cultural, or otherwise not or not just religious. It is not simply that the history of the meaning of ioudaios might be told differently if we chose a different end-point, such as the modern equivalents in Hebrew or Japanese or German. Even the English term “Jew” resists reduction to a single meaning at the end of a single story.