Mishneh Torah, Marriage 5-7

Sugya Map: Kiddushin via Forbidden Objects

• Core Issue: Does Kiddushin require an object of objective monetary value, or subjective utility to the recipient?
• Primary Sources: Kiddushin 56b; Mishneh Torah, Hilchot Ishut 5:1.
• Nafka Mina: Can a man consecrate a woman with an object forbidden by Rabbinic law, even if it remains physically valuable?

Text Snapshot

"When a man consecrates a woman with an object from which it is forbidden to derive benefit... she is not consecrated... [This ruling applies] even if the prohibition against deriving benefit from the object is merely Rabbinic in origin." (MT, Ishut 5:1).

Rambam’s language here is absolute. The nuance lies in the definition of "money" (mamon). If the cheftza (object) is legally "worthless" due to the prohibition, the kinyan (acquisition) of marriage fails.

Readings

• Rambam (MT): Formalist. If the Rabbis declare an object assur b’hana’ah (forbidden for benefit), it loses its status as mamon entirely. Therefore, it cannot effect a kinyan of kiddushin.
• Rabbenu Asher (Rosh): Pragmatic. He distinguishes between Torah-level prohibitions and Rabbinic ones. If the prohibition is only Rabbinic, the object retains its objective Torah-level monetary value, and thus, the kiddushin should be binding.

Friction: The "Value" Paradox

Kushya: If the woman could sell the forbidden object to a third party (e.g., a non-Jew) who is not bound by the prohibition, is it not "money"? If it has market value, why does the Rabbinic decree nullify the kiddushin?

Terutz (Beit Shmuel): The Beit Shmuel (28:54) argues that kiddushin requires a transaction that is valid for the parties involved. If the object is forbidden to the woman, she has received nothing of permissible utility at the moment of the kinyan. It is not a transfer of value; it is a transfer of a legal nullity.

Intertext

• SA Even HaEzer 28:21: Codifies the debate. The Shulchan Aruch tends toward the Rosh—if the prohibition is merely Rabbinic, we worry about the validity of the kiddushin.
• Responsa: Noda Biy’hudah (EH I:59) suggests that even if an object is forbidden, if it has value elsewhere, it creates a safek kiddushin (doubtful marriage).

Psak/Practice

In contemporary practice, this meta-halachic heuristic is critical: Do not rely on questionable assets for Kiddushin. If a groom uses an object of ambiguous legal status (e.g., non-kosher items, disputed property), the marriage may be void or require a get out of caution (safek kiddushin). The minhag of using a simple, plain gold ring (unadorned by jewels) is the ultimate safeguard against these kiddushin failures.

Takeaway

A valid kinyan of marriage requires the transfer of mamon that is both objectively valuable and subjectively permissible for the recipient to possess. When in doubt, simplify the kiddushin—a plain ring avoids the entire sugya.