Today’s daf introduces a situation that requires understanding a bit about the sotah, a woman accused by her husband of committing adultery.
In the Book of Numbers (5:11-31), we learn that if a husband believes that his wife has had sex with another man and becomes jealous, even if he has no evidence, he can bring his wife to the priest who conducts a test to determine if she’s been faithful. In the only example of trial by ordeal in the Torah, the priest mixes up a potion of water, dust from the Tabernacle floor and a parchment with a curse written on it in ink, which dissolves in the water. The woman is made to uncover her hair and drink the water. If the water causes “her belly to distend and her thigh to sag,” she is guilty. If it has no effect, she is presumed not guilty.
What does this have to do with levirate marriage? Let’s go back to our daf to find out.
Rav Yehuda said that Rav said: The co-wife of a sotah is forbidden. What is the reason for this? The term defilement is written in that passage dealing with the sotah: “She has been defiled secretly.” (Numbers 5:13). Similarly, defilement is written with regard to those with whom relations are forbidden in the verse: “Do not defile yourselves in any of these things, for in all these the nations are defiled, which I cast out from before you.” (Leviticus 18:24)
Over the last couple of days, the Gemara has been discussing whether a co-wife is responsible for fulfilling the mitzvah of yibbum (or halitzah) in the event that wife number one cannot do so. In the case of the sotah, Rav Yehuda says in the name of Rav that neither the sotah’s co-wife, nor the sotah herself, are responsible. The way he gets there is with a gezeira shava — an inference based on similar words appearing in two separate Torah passages. Here, that word is “defilement.”
Numbers 5:13 says that the sotah is presumed to be defiled from her suspected adultery. Leviticus 18:24 uses this same term to describe the defilement that occurs when one engages in forbidden sexual relations. Rav therefore concludes that just as forbidden sexual relations are a defilement (and thus prohibited), so is yibbum or halitzah with a sotah (or her co-wife).
The Gemara goes on to raise several objections to this ruling, and it’s easy to see why. Unlike the 15 categories of women listed as exempt from yibbum and halitzah in the opening mishnah of this tractate, the case of the sotah is one of doubt. A woman has been sequestered with a man long enough that sex could have occurred — but did it? There are no witnesses, so we don’t know. If it has, she’s forbidden to her husband — and to his brother, taking yibbum and halitzah off the table. If it hasn’t, yibbum or halitzah should be required — but how do we know?
Since we can’t be sure, the ruling is to prohibit yibbum and halitzah. The greater good is to keep her husband’s brother from violating a negative commandment by sleeping with someone forbidden to him, which would result in a severe punishment — karet, or excision from the Jewish people. That would be a greater offense than preventing the brother from performing the positive commandment of fathering a child in his dead brother’s stead.
And what of the sotah herself? How do we know it was even her desire to be sequestered with another man? Why is she guilty until proven innocent? How come her husband gets to drag her before the priest for a trial by ordeal and, even if she’s proven innocent, he doesn’t face any consequences?
For the answers to these questions and more, we’ll just have to wait until a year from now, when we embark on learning Tractate Sotah.
Read all of Yevamot 11 on Sefaria.