(Photoillustration by Tablet Magazine. Original photo: Marc Chagall: Tamar, Daughter-in-Law of Judah, 1960.)
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Sex With Your Uncle? OK. Sex With Your Widowed Daughter’s Rival? Not OK.

When two mitzvot conflict, the Talmud asks, how do we decide which takes precedence?

Adam Kirsch
October 14, 2014
(Photoillustration by Tablet Magazine. Original photo: Marc Chagall: Tamar, Daughter-in-Law of Judah, 1960.)

Literary critic Adam Kirsch is reading a page of Talmud a day, along with Jews around the world.

This week, Daf Yomi readers began a new division of the Talmud: Seder Nashim, which as its title suggests is primarily about matters pertaining to women, including the laws of marriage and divorce. (Though not exclusively: Nashim also includes tractates devoted to other kinds of vows besides the marital one, including the Nazirite vow.) The first tractate in this Seder, or Order, is Yevamot, which literally means “sisters-in-law.” Its particular focus, however, is the practice known as levirate marriage, which is most famous in the Torah from the story of Judah and Tamar. In that episode from Genesis, Tamar is married to Judah’s son Er, who dies before fathering any children. As a result, Er’s brother Onan is made to marry Tamar, in order to “fulfill [his] duty as a brother-in-law to raise up offspring for [his] brother.” Onan, however, refuses to consummate the marriage, instead “spilling his seed upon the ground”—and thereby earning himself eternal fame, or infamy, as the inventor of onanism.

This type of union, known as levirate marriage (the English word comes from the Latin term meaning “brother-in-law”), is designed to prevent the dead husband’s lineage from dying out: His brother impregnates his wife in order to provide him with a posthumous heir. The practice is commanded in Deuteronomy 25:5: “If brothers dwell together and one of them dies and he has no child, the wife of the dead man shall not be married outside of the family to one not of his kin; her brother-in-law will have intercourse with her and take her to him to be his wife and consummate the levirate marriage.” There is, however, a significant problem with this commandment, because it seems to directly contradict an earlier prohibition from the book of Leviticus: “You shall not uncover the nakedness of your brother’s wife; it is your brother’s nakedness.” When two mitzvot conflict, the Talmud asks, how do we decide which takes precedence?

The mishna on Yevamot 2a begins by considering one of the numerous problems raised by levirate marriage. Ordinarily, a man is forbidden to have sex with his brother’s wife; it is only because of the positive commandment of levirate marriage that this prohibition is suspended. What happens, however, if the brother’s wife, the yevama, is also forbidden to the man on other grounds, because she is related to him in some other way? There are, the mishna explains, no fewer than 15 types of relationship that are considered incestuous and forbidden by law. A man may not have carnal knowledge of his daughter or granddaughter, or his step-daughter or step-granddaughter, or his mother-in-law, or his grandmother-in-law, to name just the most obvious categories.

Keeping track of all the genealogical relationships at play here is extremely complicated—so much so that, as the Koren Talmud’s introduction explains, “Yevamot is considered one of the hardest, most complex tractates in the entire Talmud.” To help meet the challenge, the Koren editors have devised a whole series of genealogical tables, with special icons indicating different types of relationship. It already seems that Yevamot is going to rival Tractate Eruvin as a test of logical reasoning and memory.

Say, for instance, that a man has a daughter, who grows up to marry his brother, her own uncle. (This is entirely permissible under Jewish law.) In this case, the father is brother-in-law to his daughter. Now say that his brother dies, and he is left facing the obligation to marry the widow—which means, in this case, to marry his own daughter. Which prevails, the commandment to levirate marriage or the incest prohibition? The mishna explains that in this case, as with all the 15 categories of forbidden relationships, the prohibition governs: A man can never marry his own daughter (or his granddaughter, or his mother-in-law, and so on), even if she is the widow of his brother.

This is, however, only the first stage of the discussion. Remember that, in biblical and Talmudic times, Jewish society was polygamous: It was perfectly legal for a man to marry several women (just look at Jacob, with his two wives and two concubines). It might very well happen, then, that a man would be obligated in levirate marriage to two of his dead brother’s wives. What would be the law, however, if one of those wives was prohibited to him because she belonged to one of the 15 forbidden categories? Would he still have to marry the other wife—what the Talmud calls the “rival wife”? The answer is no: If you are exempt from marrying one of your dead brother’s wives because you are related to her, you are also exempt from marrying her rival wife, even if she is a stranger.

And, characteristically, the Talmud takes the matter a step further still. Say your brother marries your daughter—call her A—and another woman—call her B. If your brother dies, you do not have to marry A, because she’s your daughter, and you’re also exempt from marrying B, because she’s your daughter’s rival wife. Now say that B goes on to marry another man, C, who also has a second wife, D. (See why the diagrams come in handy?) Then C dies, and D—your daughter’s rival wife’s rival wife—is left childless. Do you have to marry her? Again, the mishna says no: A rival wife’s rival wife is exempted, and so on to the nth degree.

The mishna goes on to explain that levirate marriage is only required if your dead brother was actually married to his wife at the time he died. If the couple were divorced, you are under no obligation to marry your dead brother’s ex-wife. Again, if the wife is an aylonit—a woman who is biologically unable to bear children—the obligation of levirate marriage is voided. After all, the whole purpose of the institution is to provide the dead brother with an heir; if his widow is infertile, this would be impossible.

So far, we have only been talking about the first mishna in Yevamot. In the Gemara, starting on 2b, the discussion turns from these particular forbidden relationships to the broader principle behind them. Levirate marriage is a positive mitzvah, while the ban on various kinds of incest is negative mitzvah. For instance, one of the 15 forbidden relationships is that between a man and his wife’s sister: “And you shall not take a woman to her sister, to be a rival to her, to uncover her nakedness, with her in her lifetime,” says Leviticus. As a result, if two brothers marry two sisters, and one of the brothers dies, the survivor does not have to marry his dead brother’s wife, who is also his wife’s sister.

Yet as the Gemara points out on Yevamot 3b, this seems to contradict a general rule of Talmudic law, which is that a positive mitzvah overrides a negative one. The rabbis go on to list several examples of this principle from other areas of law. For instance, the Torah prohibits wearing garments made from shatnez, a mixture of wool and linen. Yet when it comes to making tzitzit, it is permitted to put wool fringes on a linen garment: In this case, the positive commandment to wear tzitzit overrides the negative commandment about shatnez. Again, Leviticus prohibits a Jew to shave the corners of his hair or beard; but when a leper is seeking ritual purification, he is commanded to shave off all his body hair, even his eyebrows. Here, too, the positive commandment regarding purification seems to override the negative commandment about hair-cutting.

This discussion involves the rabbis in complex disagreements about the proper way to interpret scripture. Can meanings be deduced by juxtaposition—that is, does a verse have some logical relationship to the verses before and after it? If so, perhaps some of the rules about positive and negative commandments can be elicited that way. Or does the question depend on the punishment for the sins at issue—so that a positive commandment might override a prohibition enforced by whipping, but not one enforced by karet, spiritual excommunication? The pursuit of these questions is still ongoing, and I’m looking forward to seeing where the rabbis will lead us next.


To read Tablet’s complete archive of Daf Yomi Talmud study, click here.

Adam Kirsch is a poet and literary critic, whose books include The People and the Books: 18 Classics of Jewish Literature.

Adam Kirsch is a poet and literary critic, whose books include The People and the Books: 18 Classics of Jewish Literature.