Should Leviticus 18:18 Be Understood as Prohibiting Polygyny?

A Response to David Wilber

by Jason Caissie, Jesse ben Yosef, and Brian Somers

This short treatise is a response to David Wilber’s article “Does the Torah Prohibit Polygamy? An Examination of Leviticus 18:18,” in which the author has given a handful of reasons why he interprets Leviticus 18:18 as a general commandment against the practice of polygyny, defined as one man being married to more than one woman at the same time. Now because Wilber promises us that an article in greater detail is yet to come, this treatise will respond primarily to his claims regarding Leviticus 18:18.

As a disclaimer, this response should not be taken as an overt support of polygyny; rather, it is simply a scholastic disagreement on Wilber’s textual interpretation of Leviticus 18:18, co-authored by several men who are each quite happy to call themselves “the husband of one wife.”

The text in question is as follows:

And thou shalt not take a woman to her sister, to be a rival to her, to uncover her nakedness, beside the other in her lifetime.” (Leviticus 18:18 JPS)

Wilber’s argument, summed up, is that this passage, when interpreted “correctly” by his estimation, serves as a blanket prohibition against polygyny within Torah law. He does this by making four claims, which will be addressed in the following response.

First Argument

Wilber’s first argument essentially hinges upon the translation of the Hebrew phrase “ishah el-achotah,” which is commonly translated as “a woman to her sister,” and is generally understood to be a prohibition against being married to both a woman and her sister at the same time. Wilber argues that instead of “a woman to her sister,” the phrase should actually be translated idiomatically as “one to another,” as it is used multiple other places in the Scriptures. Wilber writes, “…Since this phrase is used in this way everywhere else in the Bible, it doesn’t make sense to interpret Leviticus 18:18 as referring to literal sisters. The word ‘sister’ in Leviticus 18:18, therefore, ought to be understood broadly as a female in general.” In support of this, he then appeals on scholastic authority to the (alleged) Qumranic interpretation of Leviticus 18:18 from the Dead Sea Scrolls.

Does Wilber’s first argument hold water? Respectfully, we would suggest that it does not, for the following reasons:

First, Wilber’s appeal to the Dead Sea Scrolls is, frankly, misplaced. Wilber writes, “…this interpretation of Leviticus 18:18 was shared by the Qumran community.” He appeals to the opinion of Biblical scholar Angelo Tosato, who suggested regarding a few passages from the Dead Sea Scrolls, that “Qumran’s interpretation of Leviticus 18:18 is not only correct but even more faithful to the original sense than the interpretation commonly given today.” Now no disrespect is intended here, but this claim is simply inaccurate. Admittedly, the Qumran sect made no attempt to hide their disdain for polygyny; however, the problem with Tosato’s assertion (and by extension, Wilber’s) is that neither of the passages referenced (11QT 57:15-19 and CD 4:19-5:4) were textually connected to Leviticus 18:18. By Wilber’s own admission, both of these passages, rather, were commentaries on Deuteronomy 17:14-20 regarding the prohibition against kings multiplying horses, gold, and wives. (The actual Qumranic text of Leviticus 18:18, meanwhile, agrees implicitly with the Masoretic text.) This point is emphasized because unlike Leviticus 18:18, the commandments contained in Deuteronomy 17:14-20 regulate the activities of Israel’s king, and not its common citizens. And while the idea that an ancient sectarian commentary on Deuteronomy 17:14-20 should be somehow connected to Leviticus 18:18 is, perhaps, interesting, it is, in the end, simply that: an idea, and not a solid conclusion.

The second problem with Wilber’s first argument is it simply has no historical basis. Not only does his interpretation of “ishah el-achotah” lack the support he claims from the Dead Sea Scrolls, but there exists centuries of Jewish theology to its contrary. The truth of the matter is that Jewish scholars throughout the centuries, all of whom have been intimately familiar with the phrase “ishah el-achotah” have only ever understood this passage as referring to a prohibition against marrying literal sisters. Consider the following historical testimonies:

Additionally, no reputable translation of the Scriptures agrees with Wilber’s proposed retranslation of “ishah el-achotah” in Leviticus 18:18 to “one to another;” rather, Biblical translators unanimously understand that “ishah el-achotah” means, contextually, “a woman to her sister.” Now admittedly, a widespread belief in something does not guarantee its accuracy; however, the complete lack of historical and scholastic support for Wilber’s proposed retranslation of “ishah el-achotah” does strongly suggest that Wilber’s idea cannot be taken seriously as anything more than an intriguing, though ultimately unsupported, theory.

Second Argument

Wilber’s second argument is that because Leviticus 18:18 uses the preposition “to” (el) instead of the conjunction “and,” (vav) the commandment should “be understood idiomatically in the distributive sense.” Wilber writes further, “If it were referring to two literal sisters, we would expect the phrasing of the verse to be consistent with the other anti-incest laws of Leviticus 18.” Now, like Wilber noted, the conjunction “and” is used in Leviticus 18:17 to identify an explicitly forbidden relationship in marrying a mother and her daughter; but the fact is that in Leviticus 18:18 the preposition “to” is used rather than the conjunction “and” in describing the taking of a woman “to her sister.” It seems as if Wilber is trying to reason that inconvenient fact away by appealing to some idiomatic understanding of the “distributive sense.” 

But what does that really mean? In a sense, it means that Wilber’s argument here actually strengthens our objection: that Leviticus 18:18 doesn’t fall in the same category as the anti-incest laws. The conjunction “and” has been used repeatedly in the previous verses to denote forbidden relationships; yet here we come to the preposition “to,” thus denoting a new, unique thought process on the part of the author. 

Setting this aside, here is the biggest problem with Wilber’s second argument: the wording of law is supposed to be clear. If a specific law is supposed to mean something other than what is plainly read, then how can a Righteous Lawgiver penalize someone for following the plain interpretation of that law? What if a governmental law required knowledge in idioms to properly understand and follow it? What if that law would otherwise be interpreted to mean something totally different than the plain reading by using a Hebrew idiom? How could a righteous government enforce that law on someone who is not familiar with the idiom, or penalize one that read the law and followed the plain reading of it? Does it make sense for any local lawgiver to use idioms in their law and then punish someone for breaking that law for using that phrase literally?

The answer to all of these questions should be clear: God is not the author of confusion, (1 Corinthians 14:33) but of order. (1 Corinthians 14:40) It does not make sense for the Creator of the Universe to send a secret code in His law which was only revealed to an extremely few number of people, able to crack the code several thousand years after the fact, that His instructions really mean something totally different than the plain (and historically accepted) reading. It is therefore unfathomable that a Righteous Lawgiver, who declares that He will hold His people accountable for their observance of the decrees that He gave, (Matthew 7:21-23) would be so negligent in giving His commandments as to give one with such convoluted verbiage.

Third Argument

Wilber’s third argument speculates that the reason why this commandment was given was “to prevent rivalry between the two wives.” He makes the assumption here that multiple wives automatically results in rivalry, and to support this assumption, he points to Sarah and Hagar, and Penninah and Hannah, neither of whom are known to be literal sister-wives. (We’ll return to these examples later and discuss them in greater depth.) Now thus far, his arguments have been focused on matters of interpretation; however, where Wilber now seeks to explore the matter of causation of rivalry, the Torah itself discusses the matter of intent. This distinction is evident from the fact that the purpose of the commandmentas stated explicitly in the text– was to be a prohibition against a man taking his wife’s sister as a wife “to be a rival” to her in her lifetime. It was never to be to a blanket law prohibiting a man from taking a second wife; rather, it was given as a protection to women in cases where her husband’s intention was to vex his first wife by taking her sister “to be a rival to her.” This is, and historically always has been, the clear meaning of the text, as will be shown below.

The 12th century Jewish sage Rabbi Nachmanides wrote in his exhaustive commentary on the Torah something very specific regarding the phrase “to be a rival” in Leviticus 18:18: “With this the Torah explains the reason for the prohibition. It is saying that it is not proper to take a woman and her sister to make them rival wives, to vex one to another, because it is fitting they should love one another and not be rival wives.” Similarly, Targum Onkelos, an Aramaic paraphrase of the Torah dating to the end of the 1st century AD, agrees with Nachmanides on Leviticus 18:18, saying, “And a wife with her sister thou shalt not take to cause her tribulation by uncovering her nakedness over her in her life (time).”

Earlier, we noted that Wilber pointed to Sarah and Hagar, and Penninah and Hannah as examples of non-sister co-wives who were rivals. A closer examination of these two sets of co-wives seriously weakens his argument and agrees with Nachmanides and the Targum Onkelos. Let’s look first at Penninah and Hannah. In 1 Samuel 1:6, the word translated as “adversary” (NJPS) or “rival” (NRSV) is “tsarah,” which has the given meanings of (1) straits, distress, trouble and (2) vexer, rival wife. (The first two uses of tsarah in the Torah are Genesis 35:3 and 42:21.) The vexer is not Hannah, but Penninah, as the text reads “[h]er rival used to provoke her severely, to irritate her, because the Lord had closed her [Hannah’s] womb.” This is one wife feeling superior to the other wife because she has borne children to Elkana while the other wife has not borne him children.. This has nothing to do with their shared status as wives to Elkanah. Moreover, Hannah prayed to YHVH and was heard in her distress (as a second wife) and was given a son who became a great prophet. Considering the situation of Sarai and Hagar, Hagar was Sarai’s slave handmaiden. (Genesis 16:1) Sarai gave Hagar to Abraham her husband [he did not choose to take her first] as a concubine (Genesis 16:2) to obtain children through her. When Hagar conceived, she thought less of her mistress, which goes with thinking more highly of herself. (Genesis 16:4-5) Hagar ran away after being disciplined harshly by Sarai, and encountered the Angel of the Lord in the wilderness. The Angel addressed her as “Hagar, slave of Sarai” (Genesis 16:8) and asked her where she was going. Hagar answered that she was running away from her mistress. The Angel told her to return and submit to Sarai. In a nutshell, the issue between Hagar and Sarai was that Hagar was vexing her mistress by her disrespect, not by her status as a concubine. The Angel said nothing about Hagar being given to Abram as a concubine. In both instances cited by Wilber, the vexing occured because of feelings of superiority over having provided children that the other wife hasn’t yet, not because of being co-wives.

Next, Wilber makes an interesting claim, that “…if the reason for this commandment was to avoid rivalry between co-wives, it simply doesn’t make sense that this law should be limited to literal sisters.” This claim, however, is purely speculative; further, one need look only to the difficulties that marrying sisters presents in family dynamics. Imagine that a man who is married to two sisters is to divorce one of them. (God forbid.) The family dynamic would be plunged into great chaos, as the divorced woman would never be truly out of his life, and he would be probably expected to maintain a good familial relationship with his in-laws, to whom he is still attached through the wife he did not divorce! Then there is the matter of the Torah’s use of the phrase “in her lifetime” to be considered. Imagine that a man divorces his wife, (God forbid) and then seeks to marry her sister afterwards. The family dynamics would still be sheer and utter insanity for much of the same reasons, as those same in-laws who he once removed from his life (along with his first wife) he is now attempting to graft himself back into. Now admittedly, these examples are, perhaps, an extreme edge case; however, they serve well as a potential example as to why Leviticus 18:18 pertains to sisters as opposed to unrelated women, as the family dynamics at play behind marrying two sisters is vastly different than those at play behind marrying two or more unrelated women.

To sum it up: Wilber asserts in his third argument that Torah prohibits the taking of a second wife because it will produce rivalry, when in reality, the Torah’s intent is to prohibit the taking of a second wife if the intent is to produce rivalry which causes defilement -- specifically in the case of biological sisters, when the potential of doing so is significantly increased.

Fourth Argument

Lastly, Wilber’s fourth argument is that because of literary style of the Hebrew, Leviticus 18:18 should be read as belonging to a separate part of moral injunctions than the anti-incest laws of Leviticus 18:7-17. Wilber speculates, “Leviticus 18 presents two separate units of laws—the first unit dealing specifically with laws prohibiting various incestuous relationships and the second unit dealing with laws governing sexual morality more generally.”

Wilber tries to make a contextual argument about the literary structure of Leviticus 18. He is right about verse 18 starting a new literary unit because verses 6-17 all begin with “You shall not uncover the nakedness of (…).” He terms the section of verses 6-17 the “anti-incest” laws. One notes right here that means taking a wife’s sister as a second wife is not part of the so-called “anti-incest” laws. Wilber is silent about the fact that there is a distinction made between a man’s mother and his father’s wife (see Leviticus 18:7-8). He is also silent about the fact that there are two kinds of sisters-in-law (a man’s brother’s wife or his wife’s sister). The brother’s wife falls into the “anti-incest” category, but the sister’s wife does not fall into this category.

Wilber looks at several places to find the phrase “a woman to her sister” in Hebrew, but what he does not do (and note must here be taken that he said he intended to produce a video addressing the other scriptures) is look at related scriptures such as Leviticus 20 (this chapter was alluded to earlier in the reference to Abraham Ibn Ezra). Turning now to this chapter, we note the penalties for serious sexual infractions, up to and including death. These penalties put teeth into the prohibitions of Leviticus 18.

A careful look at this list shows there is no punishment for taking a wife’s sister, much less taking a second wife in general. If there is sin, it is in causing deliberate rivalry between two sisters, or diminishing what he has been giving the first wife in order to provide for subsequent wives for which the remedy was for the first wife to go out free. (Exodus 21:11)

Additional Considerations

For almost every Biblical argument, there is likely one “scholar” that has a different understanding than another “scholar.” We have listed several scholars and Rabbis, spanning centuries, in support of the traditional understanding of Leviticus 18:18. In Wilber’s article, he quoted four scholars: three of these scholars were born and studied mainly in the United States, (one of those three did get his PhDs in England) and one was born in Italy and studied in Rome. While there is no doubt that these scholars are/were well versed in Hebrew, it cannot be contested that King David and the writers of the Talmud knew Hebrew of that era and Hebrew idioms better than the best of the ancient Hebrew scholars of today. We are now going to turn our attention to their testimony and understanding of Leviticus 18:18 to solidify our response.

The Talmud, Sanhedrin 21a, shows a debate between several Rabbis debating about the maximum number of wives that Deuteronomy 17:17 would allow a king to have. In that debate, 2 Samuel 12:8 was used in support of their conclusions, which reads, “I [YHVH] gave thee [King David] thy master’s house, and thy master’s wives into thy bosom, and gave thee the house of Israel and of Judah; and if that were too little, then would I add unto thee so much more.” (2 Samuel 12:8) The following discussion then takes place between a number of Rabbis:

“Whence do we deduce the number eighteen? — From the verse, And unto David were sons born in Hebron; and his first-born was Ammon of Ahinoam the Jezreelitess; the second, Chileab of Abigail the wife of Nabal the Carmelite; the third Absalom the son of Maacah; and the fourth, Adonijah the son of Haggith; and the fifth, Shefatiah the son of Abital; and the sixth, Ithream of Eglah, David’s wife. These were born to David in Hebron. And of them the Prophet said: And if that were too little, then would I add unto thee the like of these, [Ka-hennah] and the like of these, [we-kahennah], each ‘kahennah’ implying six, which, with the original six, makes eighteen in all. Rabina objected: Why not assume that ‘kahennah’ implies twelve, and ‘we-kahennah,’ twenty-four? It has indeed been taught likewise: ‘He shall not multiply wives to himself beyond twenty-four.’ And according to him who interprets the redundant ‘waw,’ it ought to be forty-eight. And it has been taught even so: ‘He shall not multiply wives to himself, more than forty-eight.’” (Sanhedrin 21a)

We do not believe that the Talmud is 100% historically accurate, nor do we elevate any Rabbi’s conclusion of a law to the status of the law itself; (“Scriptural Authority”) however, we do believe that the writers of the Talmud and the Rabbis debating the issues therein fully understood the plain reading of the Torah, and undoubtedly understood the Hebrew better than anyone born and studied many centuries later in non-Hebrew-speaking lands. In the above Talmudic discussion, we also do not see any of these Rabbis pointing to Leviticus 18:18 and claiming the maximum number of wives is obviously just one, and that King David was sinning by taking more. Why not? Did none of these Rabbis know Hebrew or Hebrew idioms as well as the few scholars that claim that this verse limits a man to one wife?

If Wilber’s conclusion is correct, that Leviticus 18:18 was actually a prohibition to polygyny, then surely, without any doubt, King David (and other polygynists mentioned in the Scriptures that were considered to be righteous) would have read that law and be in agreement with its interpretation. When it came to understanding the Torah, King David believed (and the Holy Spirit confirmed) that he had a better understanding than many of the scholars of his time and before: I have more understanding than all my teachers; for Thy testimonies are my meditation. I understand more than mine elders, because I have kept Thy precepts.” (Psalm 119:99-100) Now since there can be no doubt that King David understood the proper textual understanding of Leviticus 18:18, if Wilber’s understanding of Leviticus 18:18 was true, then we would have no choice but to view King David as being in open rebellion to the Father’s commandments. Yet if King David was in open rebellion in this area, then wouldn’t the Father have penalized him, or at least mentioned it to him? Would the Creator of the Universe overlook this open defiance of the Torah by the current leader of His people? Would the Scriptures still have such good words to say about King David? Would not unrepentant sin define King David as an evil king? Why is there no evidence in the Scripture that King David was at least remorseful for the “sin of polygyny?” Most importantly, when the prophet Nathan was chastising King David about his adultery and murder, why would he say that if the wives that the Father gave King David was not enough, then He would have given him more? If King David was intentionally transgressing the Torah by taking multiple wives, then surely, the following verse would have read very differently: “…because David did that which was right in the eyes of the LORD, and turned not aside from any thing that He commanded him all the days of his life, save only in the matter of Uriah the Hittite.” (1 Kings 15:5, emphasis added)


Wilber adduces four arguments in support of his contention that Leviticus 18:18 is a blanket ban on polygyny. These arguments are (1) the use of the term “ishah el-achotah” as used elsewhere in scripture implies the general case of a “woman to another woman” instead of the specific instance of a “woman to her sister;” (2) a scholar’s opinion on what the Hebrew should be understood to be saying; (3) the intent was to prevent rivalry between wives, not just rivalry between sisters, and (4) Dr. Copan’s argument that the literary structure of Leviticus 18 points to general prohibited sexual relationships as opposed to anti-incest laws. We have shown that contrary to Wilber’s assertion in his first argument, the Dead Sea commentary was specific to kings in Deuteronomy 17:14-20, and the historical understanding of Judaism’s greatest sages understood Leviticus 18:18 as literally referring to a woman and her sister. For Wilber’s second argument, we counter with the common-sense notion that the straightforward literal reading is what’s intended to convey YHVH’s thoughts with the maximum clarity, so uneducated (and for that matter, educated) people can hear and obey. Wilber’s third argument was an appeal to the conflicts between Sarai and Hagar, and Penninah and Hannah; yet we have shown them to be conflicts over the number of children one wife had while the other wife having none, which is not the same thing as taking a wife to vex the first, as Sarai gave Hagar to Abram, and Elkanah loved Hannah for herself. Finally, Wilber’s fourth argument fails due to the fact that Leviticus 20 does not include the prohibition of plural marriage outside of prohibited kinship bonds. 

To conclude, we cannot accept Leviticus 18:18 being anything more than a specific prohibition for a husband to take his wife’s sister as an additional wife if his intent is to vex his first wife. Where the text says, “And thou shalt not take a woman to her sister, to be a rival to her,” we accept that the text simply means what it says: “And thou shalt not take a woman to her sister, to be a rival to her.”

*For more Scriptural defense and insight on this topic, click here: Polygyny 


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Vermez, Geza. The Complete Dead Sea Scrolls in English. 1st ed., The Penguin Group, 1997, pp. 130, 213.

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Abraham Ibn Ezra, Commentary on the Torah on Leviticus 18:18. Translated by Jay F. Shachter. Retrieved from

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