Nedarim 9a: The Nature of Yad and Kabbalah in Neder and Shevu'ah

This shiur on Nedarim 9a presents a deep analysis of the mechanics of nedarim (vows), focusing on the Ran's approach to kabbalah and the conceptual structure of yad (incomplete vow language). Rabbi Zweig begins by addressing an apparent contradiction in the Ran: earlier, the Ran stated that there cannot be a neder without an issur chefetz (prohibition on an object), yet later he seems to validate neder hedish (sanctification vows) based on kabbalah (commitment). The resolution is that every neder hedish contains two elements: the kabbalah itself and the resulting shibud nechasim (monetary lien). The commitment creates certainty, and that certainty generates the issur chefetz—the lien on property that tzedakah acquires. Thus, the Ran is consistent: a neder always requires an issur chefetz, but in neder hedish, that chefetz arises from the kabbalah. Rabbi Zweig contrasts this with the approaches of the Rosh and the Rambam (רמב"ם). According to the Rosh, a neder of issur directly changes an object (making it forbidden), while a neder of hedish is built on one's word—a commitment to perform an action. The Ran adds nuance: kabbalah alone, without resulting in an issur chefetz, is not a full neder but still creates a binding commitment recognized by the Torah (תורה). This is learned from the concept of tzedakah, where saying "I will give" creates a lien on one's property in favor of the poor. The pasuk of "bal yachel devaro" (he shall not violate his word) applies to the issur chefetz, but the commitment aspect itself is rooted in the obligation of befichah (what comes from one's mouth). The shiur explores whether this kabbalah element, standing alone, constitutes a Torah-level obligation, and what the name of that issur would be—possibly an issur befichah, though not explicitly a neder in the classic sense.