Deuteronomy 23

Sugya Map

• The Problem: The prohibition of a man marrying his "father’s wife" (Deut 23:1) and the prohibition of "uncovering his father’s skirt" (Deut 23:1b).
• Primary Nafka Minot:
  • Halakhic Status: Does lo yikach ("he shall not take") imply that Kiddushin (marriage) is legally void (ein kiddushin tofasin) or merely prohibited le-chatchila?
  • Definition of Mamzerut: Defining the exact range of forbidden unions that produce a mamzer (offspring of forbidden relations).
  • Juxtaposition (Semichut): Why does the Torah place the laws of the mamzer and the petzua daka (crushed testes) immediately after the prohibition of the father’s wife?
• Primary Sources: Deuteronomy 23:1–2; Kiddushin 67b–68a; Yevamot 4a, 49a; Rashi (ad loc); Mizrachi (ad loc); Ha’amek Davar (ad loc).

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Text Snapshot

• Deuteronomy 23:1: "לא יקח איש את אשת אביו ולא יגלה כנף אביו"
• Linguistic Nuance:
  • Lo yikach (לא יקח): Rashi notes this is not a directive ("thou shalt not take"), but a statement of ontological impossibility ("he cannot take"). The terminology suggests ein kiddushin tofasin—the legal act of marriage fails to initiate a status change.
  • Kanaf (כנף): Literally "wing" or "skirt." Ha’amek Davar (ad loc) distinguishes between chuppah (the full garment of the groom) and kanaf (a partial covering). The kanaf here functions as a metaphor for the father’s authority or potential marital access, specifically in cases like a shomeret yavam (a widow awaiting the brother-in-law).

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Readings

1. The Ontological Shift (Rashi and Mizrachi)

Rashi, drawing on Kiddushin 67b, posits that "he shall not take" is a declarative statement regarding the legal efficacy of the act. Mizrachi provides the rigorous underpinnings for this: if the verse were merely a prohibition, the Torah would have used the language of lo yigaleh (as seen in Lev 18:8). By using lo yikach, the Torah signals that the status of "wife" cannot be applied to this woman in relation to the son. The chiddush is the distinction between a lav (prohibition) that carries a penalty, and an act that is me’ikara (from the start) legally null.

2. The Semantic Range of "Kanaf" (Ha’amek Davar)

Rabbi Naftali Zvi Yehuda Berlin offers a sociological-legal read. He argues that the kanaf represents a union that lacks the formal chuppah of a primary marriage. He links this to the imagery in Ruth 3:9 ("spread your wing/skirt over your handmaid"). By referencing the yavam (levir), the Ha’amek Davar suggests that the verse covers relationships that exist in a grey area of "potential marriage" rather than full nissu’in. The chiddush here is that kanaf acts as a linguistic bridge between the sanctity of a father’s marital bond and the quasi-legal status of a widow awaiting a yavam.

3. The Structural Logic of Mamzerut (Mizrachi)

Mizrachi synthesizes the semichut (juxtaposition) of the mamzer law to the father’s wife. Why does the mamzer definition appear here? Because the shomeret yavam of one’s father is the paradigm of a chayvei keritot (an offense punishable by excision). Mizrachi explains that the logic of the mamzer is derivative: if the union is one that carries the penalty of karet (excision), the offspring is a mamzer. This anchors the definition of mamzerut not in the severity of the court’s punishment, but in the divine status of the prohibition itself.

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Friction

The Kushya: If the prohibition of the father’s wife is already covered by the general prohibition of arayot (forbidden relations) in Leviticus 18, why repeat it here? Furthermore, if the prohibition against the shomeret yavam is already implied by the prohibition of dodato (one's aunt), why the redundancy?

The Terutz:

1. Redundancy for Legal Effect: As Rashi notes (based on Yevamot 4a), the repetition is intended to increase the number of lavin (negative commands) violated. This is a "doubling down" of the prohibition to emphasize the gravity of the act.
2. The Pedagogical Juxtaposition: The terutz offered by the Ba'alei Tosafot (cited by Mizrachi) is that the Torah places the mamzer law here to define the mechanism of mamzerut. By juxtaposing it with the shomeret yavam (a case of keritot), the Torah establishes a rule: mamzerut is not merely about forbidden relations, but about relations that carry the specific, severe status of karet. The petzua daka (crushed testes) is an "intervening" passage, but because the petzua daka cannot produce offspring, it is legally irrelevant to the chain of mamzerut, thus allowing the semichut of the father's wife and the mamzer to remain structurally intact.

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Intertext

• Leviticus 18:8 / 20:11: The original prohibitions regarding the "father’s nakedness." The Deuteronomy text acts as a clarification of the legal status (the kiddushin issue) rather than the mere fact of the prohibition.
• Ruth 3:9: The use of "spreading the kanaf" as a request for levirate marriage. This confirms the Ha'amek Davar’s reading that kanaf is a technical term for the marital bond between a widow and her yavam.
• SA Even HaEzer 15:1: The codification of ein kiddushin tofasin in cases of arayot (forbidden relations). The Rambam and Shulchan Aruch rely directly on the drasha from Kiddushin 67b which interprets lo yikach as ontological nullity.

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Psak/Practice

In modern psak, the principle of ein kiddushin tofasin remains the bedrock of marriage law. If a union is technically classified as an ervah (e.g., father’s wife), no religious divorce (get) is required because no marriage ever existed. The meta-psak heuristic here is that the Torah defines the legal capacity of an Israelite—some actions are not merely sinful, they are "null and void" in the eyes of the qahal (congregation). The mamzer status is the extreme consequence of this, serving as a permanent societal marker of the violation of the qahal’s boundaries.

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Takeaway

The prohibition of the father’s wife is not merely a restriction of behavior, but a definition of legal boundaries; it establishes that certain unions are so antithetical to the sanctity of the qahal that they cannot even exist in the realm of legal fiction. The mamzer is thus the social manifestation of a relationship that the law refuses to acknowledge as a union.