Mishneh Torah, Levirate Marriage and Release 6-8

Sugya Map

• Issue: The intersection of yibbum (levirate marriage) as a positive commandment (aseh) and various prohibitions (lav or aseh).
• Nafka Mina: Whether the yavam acquires the yevamah as a wife if he transgresses and engages in relations, and whether such an act releases her co-wife (tzarah) from the bond of zikah.
• Primary Sources: Deuteronomy 25:5–9; Yevamot 8a–b, 20a, 56a; Mishneh Torah, Hilchot Yibbum v'Chalitzah 6:10.

Text Snapshot

• MT 6:10: "If he transgresses and engages in relations with a yevamah who is forbidden to him because of a negative commandment... he acquires her in a definitive manner and must divorce her with a get."
• Nuance: Rambam emphasizes that while the Sages decreed against this a priori to prevent repeated sin, the kinyan (acquisition) remains effective bedi'avad (ex-post facto) because the positive commandment of yibbum possesses the inherent power to override a prohibition.

Readings

• Sha'agat Aryeh (Siman 33): Questions why yibbum overrides a prohibition (lav) but not an aseh. If the yevamah is subject to an aseh, yibbum shouldn't override it—why is one aseh "stronger" than another?
• Ohr Sameach (ad loc): Argues that the prohibition is not an independent entity but is contingent upon the kinyan of yibbum. Since the prohibition exists only because he is creating a marriage, the aseh of yibbum necessarily displaces the prohibition it creates.

Friction

• Kushya: If the yevamah is forbidden by an aseh (e.g., a kohen and a g'rusha), she is a priori unfit for yibbum. How can the yavam effect a kinyan if the act is fundamentally forbidden?
• Terutz: As the Maggid Mishneh notes, the prohibition is often a lav haba miklal aseh (a negative commandment derived from a positive one), which is structurally weaker than a direct lav. The aseh of yibbum thus acts as a docheh (pusher) against the weaker prohibition.

Intertext

• SA Even HaEzer 174:3: Discusses the hierarchy of yibbum vs. chalitzah in cases of sh'niyot (secondary rabbinic prohibitions), cementing the Rambam’s view that the marriage bond created by yibbum is legally recognized even when illicit.

Psak/Practice

The halachic heuristic is that the yibbum bond is "super-legal." Even in cases where the Sages forbid the act ab initio to prevent transgression, the underlying zikah (bond) is so potent that its consummation produces a valid marriage, necessitating a formal get to dissolve the union.

Takeaway

The power of yibbum to create a kinyan (marriage) persists even through the medium of prohibition; halacha prioritizes the fulfillment of the mitzvah bond even when the method of its fulfillment is technically illicit.