Source: Mishnah Yadayim 3:5; Tosefta Yadayim 2:13–14; Talmud Bavli Megillah 7a; Shabbat 30b.

The precise moment the Hebrew Bible became a fixed, closed canon is debated — but the Council of Jamnia (~90 AD) is the traditional anchor. Under Rabban Gamliel II at the Yavneh academy, rabbinic authorities debated the canonical status of several contested books: Ecclesiastes (Qohelet), Song of Songs, and Esther. The discussions recorded in Mishnah Yadayim (‘whether they defile the hands’ — the technical phrase for canonical status) show that these books had opponents and that their inclusion required formal ruling. The Tanakh as we have it — Torah (5), Nevi’im/Prophets (8), Ketuvim/Writings (11) = 24 books in the Hebrew count — emerges from this process.

Several important caveats: (1) The Torah and most of the Prophets were functionally canonical centuries earlier. Jamnia clarified the edges, not the core. (2) The Septuagint (LXX), the Greek translation used by diaspora Jews and early Christians, included additional books (Tobit, Judith, Maccabees, Sirach, Wisdom of Solomon, Baruch) that Jamnia excluded — these become the Catholic/Orthodox deuterocanon and the Protestant Apocrypha. This divergence directly produces the Protestant-Catholic canon dispute of the Reformation. (3) The Samaritan Pentateuch canon is only the Torah — no Prophets or Writings.