Mishneh Torah, Levirate Marriage and Release 3-5

Sugya Map

• Issue: The limits of a husband's testimony regarding his own progeny (the Migo heuristic) and the evidentiary standards for Yibbum release.
• Nafka Mina: Can a man's declaration of paternity—even when it creates a Yibbum obligation or serves to nullify one—be treated as absolute, or is it tempered by external chazakot (presumptions)?
• Primary Sources: Bava Batra 134b; Yevamot 104a–106b; Rambam, Hilchot Yibbum 3:1–11.

Text Snapshot

"כְּשֶׁאָמַר אָדָם זֶה בְּנִי אוֹ אָמַר יֵשׁ לִי בָּנִים הֲרֵי זֶה נֶאֱמָן... שֶׁאִלּוּ רָצָה לְשַׁקֵּר הָיָה מְגָרֵשׁ אִשְׁתּוֹ בְּגֵט." (Mishneh Torah, Hilchot Yibbum 3:1)

The Rambam anchors the husband's credibility in Migo (argument of "had he wanted to lie, he could have acted legitimately"). The dikduk here is critical: the husband is believed because his power to divorce is absolute.

Readings

• Ohr Sameach (3:1): Explains that since the husband could have issued a Get, his testimony regarding progeny is not "harmful" (chav) in a way that disqualifies his Migo. He views the husband’s power to change the status quo as the engine of his credibility.
• Ramban (in Chiddushei HaRamban): Challenges the Migo reliance. He posits that the husband is believed not merely due to a clever legal fiction (Migo), but because we see his clear intent to prevent his wife from becoming an agunah.

Friction

Kushya: If the husband’s statement is a "half-claim" (Migo l'chatzi te'anah), why should he be believed for all implications (e.g., Yibbum status)? Terutz: The Rambam implies that the Torah’s law of Yakir (Deuteronomy 21:17) grants the father a unique, quasi-legislative power over his son's status. Once he asserts paternity, the Halacha treats it as a factual reality for all purposes—unless it directly contradicts a pre-established chazakah (e.g., if it is already known he has no children).

Psak/Practice

The Shulchan Aruch (Even HaEzer 156:6) codifies this: when no chazakah to the contrary exists, a husband's word on paternity is sufficient to exempt the wife from Yibbum. In modern meta-psak, this underscores a strong judicial preference for ending the igun status of a widow, prioritizing the release of the woman over the strict investigation of the husband's private knowledge.

Takeaway

The husband’s power to grant a Get creates a "zone of credibility" that the law respects. Halacha prefers the certainty of a woman's freedom to marry over the theoretical possibility that a husband might be lying to avoid the Yibbum process.