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Class #6 - Class Notes

The next set of mitzvot deal with forbidden sexual relations: incest prohibitions and other prohibitions. 

First we will define what activity is prohibited.  Next we will survey what the author has to say by way of shoresh for the incest mitzvot.  Then we will try to define which incestuous relationships are forbidden.   After that we will go on to forbidden sexual relations that are not incest.

            One thing to keep in mind: what prohibitions are missing?  There may be things we assume are prohibited, but we need look carefully at what the author says.  Of course, we will see several other related mitzvot later in our study.           
            Lurking in the background of this topic is the question of people who are forbidden to marry.  If two people are forbidden to have sex, they ought not marry each other.  Assuming they do anyway, though, it’s not so clear what happens.  In some cases, the marriage is considered entirely void; the couple has gone through the motions but has not succeeded in marrying.  In other cases the marriage is considered to have taken place but the couple is obligated to divorce.  There are also cases where the focus of the prohibition is on the couple marrying.  There, sometimes, if the marriage has already taken place the couple may stay married.  These gradations are not the primary focus of the author’s discussion of these mitzvot.

            Stylistically, we noted that the author’s presentation of the mitzvot related to tumah, taharah and m’tzora were quite straightforward.  In this set of mitzvot, though, he returns to giving us lots of mental practice in close reasoning and in following the logical process of midrash halachah.  Moments of transition, like this one, convince me that our author is thinking carefully about pedagogical approach and treating this project as a developing curriculum.  We will not do all of the midrash halachah that the author includes; we will focus in more on the content.


Mitzvot #189 – 211 forbid sexual relations between specific people.  (Mitzvah #208 is on a different topic.)  The term used in the Torah for the prohibited behavior is “t’galeh ervah,”  “to reveal nakedness.”  The rabbis understood that to mean a prohibition on sexual intercourse.  In mitzvah #189 the author explains that the definition of forbidden sex is penetration. 

            Mitzvah #188 forbids other behavior as well.  The verse that introduces the list of incest prohibition says “lo tikr’vu l’galot ervah,” “do not approach to reveal nakedness” of those people with whom intercourse is forbidden.  (Lev. 18 : 6.)  The author explains that the extra word tikr’vu must be forbidding something in addition to the intercourse forbidden by each subsequent verse. The midrash halachah the author cites traces the use of this word in various verses to conclude that there is a specific mitzvah forbidding foreplay between people who are forbidden to have sex with each other.

            The author also discusses another term used in conjunction with forbidden sexual activity.  Toevah” is usually translated as “abomination.”  It seems to add extra emphasis to certain prohibitions.  We are required not to do a given act, and that act is especially bad, toevah.  The author explains the term means something ugly, unusually bad, repulsive, so that God detests it and our engaging in that activity distances us from God’s watchful care.  The term toevah, and the author’s discussion of it, does not really explain what is so repulsive about these particular behaviors.  From a rationalist point of view, this explanation is limited.

The author explains that this mitzvah prohibits foreplay (hugging, kissing, etc.) between people the Torah forbids to have sex with each other.  The rabbis expand that notion to forbid anything that might lead to sexual fantasizing about someone the person is forbidden to have sex with.  This is true for both men and women, although the author recognizes this is a much more applicable to men.

The author gives several examples:  a man must not flirt with, smell the perfume of, leer at, ask after, a woman he may not have sex with.  But this rabbinic prohibition cannot be reduced to a list; each man must determine for himself what is inappropriate behavior for him and add personal restrictions to the rabbinic list if necessary.   The author says there is an exception for a man giving attention to his wife who is a niddah, since he will eventually be permitted to have sex with her.  But even that is somewhat limited.  There is also an exception for couples considering marriage, who need to look carefully at teach other and monitor their reactions. 

            Because these rabbinic prohibitions have a subjective aspect, the author cautions that someone might think he can ignore some of the specific behaviors the rabbis cautioned against.  He might think that he, subjectively, will not be tempted even if he does things the rabbis say he shouldn’t do.  This notion might be reinforced by descriptions in rabbinic literature of rabbis who were more lenient.  But those were exceptions for rabbis who were so involved in Torah that they were above temptation, and in any event they only made exceptions for themselves in cases where their behavior helped others to observe the Torah better. 

            The author specifically cautions his teenaged son against straying outside the lines the rabbis drew.  The language the author starts with echoes what he said in his angry tirade in mitzvah #16.  But this is different.  Here, the author says to his son later in the passage, “we” should be careful to stay on the straight and narrow.  The author and his son are on the same side, facing the same difficult temptations.  The relationship between father and son has changed substantially.

            The author has advice for men finding themselves tempted by illicit behavior:  imagine yourself burning in hell as punishment, learn Torah or say shma to distract oneself.

            The rabbis also forbade couples forbidden by the Torah to have sex with each other from being alone together.  The author lists three exceptions: father and daughter, mother and son, and a married couple who have already consummated the marriage when the woman is a niddah.  The rape of Tamar by Amnon led to a prohibition on an unmarried men and women from being alone together.  (That seems a little odd, since Tamar and Amnon were half-siblings.)  Shammai and Hillel legislated against a Jewish man being alone with a non-Jewish woman or a Jewish woman being alone with a non-Jewish man. 

            Assuming there are witnesses and warning, someone who engages in foreplay with someone he or she is prohibited by the Torah to have sex with is punishable by malkos.  Someone who breaks one of the rabbinic prohibitions is punishable by makkat mardut. 

            At the end of the essay, the author explains that Ramban does not think there is a Biblical prohibition on foreplay.  He thinks there are Biblical prohibitions on certain people having sex with certain other people, and all the rest is rabbinic.  Our author often describes differences between Rambam and Ramban, usually about what counts as one of the 613 mitzvot.  The disagreement described here is broader, though.  Rambam believes certain behavior is prohibited by the Torah, but Ramban believes the same behavior is only prohibited d’rabanan.


The author discusses the shoresh for the incest prohibitions in mitzvot #188 and 190.  He cites Rambam for why the Torah prohibits incestuous sexual relations.  The Torah would prefer that sexual intercourse would be kept to a minimum, so it prohibited sex between family members who are together much of the time and who might therefore be tempted to sexual activity.  The author says Rambam thinks the Torah wants us to have sexual relations only if the goal is procreation or a mitzvah.

 Ramban criticizes this approach.  First, if the Torah wanted us to keep our sexual activity rare, it would not have permitted a man to have multiple wives.  Further, the penalty of karet seems overly strict if the purpose of the prohibition is to limit behavior that is tolerable but just not encouraged.   The author does not mention another argument Ramban makes, which is that children from incestuous relations tend to be less healthy than other children. (See Ramban’s comment on Lev. 18 : 6.)    Ramban ends his discussion there by saying that the incest prohibitions are among the mitzvot for which people do not understand the reason.  God is good and only would require us to do things that are good for us.  God knows the benefit of these mitzvot, and God isn’t telling.  It seems to me Ramban is admitting he is not satisfied with his own understanding.  (The end of our author’s description of Ramban’s position is also a bit confusing.  The author cites the idea that there are mysterious aspects to the incest prohibitions.  That seems very similar to what Ramban says in his commentary on Leviticus.  But the author seems to be quoting, and the quote does not match Ramban’s words in his commentary.  Also, the author does not actually say he is quoting Ramban.  Rather, he says, “He, of blessed memory, says ….”  Ramban was our author’s contemporary.  We saw that translator suggest elsewhere that the text mentioning Ramban as though he was not longer alive might be a copyist’s error if the copyist was working after Ramban’s death.  The author could be quoting Ramban somewhere else.  Whatever the citation confusion, the content is reasonably clear.)

The author also cites Rambam for the notion that the Torah wants to forbid a man from having sex with a woman he has a mitzvah to respect.  The author says Rambam explains how that notion relates to the various prohibited incestuous relations, but the author declines to repeat the detailed arguments.

In the shoresh section of mitzvah #188, the author refers us back to what he said earlier when he discussed adultery in mitzvah #35.  There, he spoke of the importance of children knowing who their parents are, which is less likely where adultery is happening. 

He also says there that adultery has an aspect of theft, taking the husband’s “right” to exclusive sexual relations with his wife.  After referring to that, the author points out that these reasons apply to adultery but not necessarily to incest.  When he discusses the prohibition on a man having sexual relations with his father’s wife in mitzvah #191, the author says that would be a disgrace to the father, for whom the son has a mitzvah of respect.

Overall, the author knows he has not succeeded in articulating an entirely satisfying shoresh for incest prohibitions.  In my college anthropology course I learned that incest taboos are one of very few “human universals.”  Although cultures vary in defining exactly which relationships are considered incestuous, all human societies prohibit sexual relations between people the culture considers close relatives. 


Now we will look at each of the incest prohibitions.

            Mitzvah # 189 prohibits a man from having sexual relations with his father.  The punishment for violating this mitzvah is death by stoning, provided there are witnesses and warning.  According to Rambam, the witnesses need not see the actual penetration; they just have to see the couple in the necessary position. (Hilchot Issurei Biah 1:19.)  If a man broke this mitzvah b’shogeg, without full intention, he would be required to bring a hattat.  For example, the man might not know that the Torah prohibits this behavior, or might not know the person involved is his father.

The man having sex with his father would violate this mitzvah and also mitzvah #209, which prohibits men from having sexual relations with other men.  The author asks why the Torah would include this prohibition since another mitzvah forbids the behavior.  The author cites an interesting passage touching on that question.  (I do not know the source of that passage.)  Rabbi Yehudah says that a non-Jew who has sex with his father is punishable twice.  That statement assumes that non-Jewish men are prohibited from having sex with their fathers and with other men.  (The author will return to the question of sexual relations that are forbidden for non-Jews in later mitzvah/essays.)  One problem with Rabbi Yehudah’s statement is that the penalty for violating both of these prohibitions is death, and that punishment cannot be administered twice to the same person.  So Rabbi Yehudah must mean that someone who had sex with his father b’shogeg is punishable twice, once for breaking each mitzvah.  That way, the man would be liable for two hattat sacrifices, a result that is reasonable.  But that leaves another problem with Rabbi Yehudah’s statement.  He says non-Jews are punishable twice for this behavior, and non-Jews are not required to bring sacrifices.  So we reinterpret Rabbi Yehudah’s statement to be about Jews, and assume that Rabbi Yehudah phrased his statement about non-Jews to avoid the horrifying notion that Jews might engage in such repulsive behavior.

Mitzvah #190 prohibits a man from having sexual relations with his mother.  This applies whether or not his mother and father are married, and even if his father raped his mother.  This applies after the father dies.  If the father and mother were married, the same sexual activity also violates mitzvah #191, which prohibits a man from having sexual relations with his father’s wife.

The rabbis legislate extensions of this mitzvah, prohibiting other similar relationships.  The author mentions that when rabbinic legislation extends incest prohibitions to other relationships, those relationships are called “sh’ni’ot,” “secondary” relationships.  The rabbis forbid a man from having sexual relations with his maternal grandmother and great-grandmother, and similar relationships up the generational chain.  They also forbid a man from having sexual relations with his paternal grandmother and great-grandmother, but they did not forbid similar relationships up the generational chain.  The author explains the reason for this difference: this is a prohibition on a man having sexual relations with his mother, so it makes sense to expand the legislation governing his maternal ancestors beyond the legislation governing his paternal ancestors.  (It is hard to imagine this distinction making much practical difference.)

The author outlines the punishment for violating this mitzvah.  If there are witnesses and a warning, the man is punishable with death by stoning.  If the man violated this mitzvah b’mazid but there are no witnesses and warning, the punishment is karet.  If the violation is b’shogeg, the man brings a hattat.  If a man has sexual relations with one of the women to whom the rabbis extend this prohibition, he is punishable by malkos.  The author says nothing about the woman being punishable. 

The author also explains that this prohibition applies to non-Jews as well as to Jews.   The sh’ni’ot only govern Jews.  The author will continue adding to our knowledge of how the incest prohibitions apply to non-Jews as he works through this series of mitzvot.

Mitzvah #191 prohibits a man from having sexual relations with a woman who was ever his father’s wife, whether or not she is his mother.  In other words, he may not have sex with his step-mother, assuming his father married her.  The prohibition survives after the death of the father, and it survives divorce between his father and his father’s wife.  The prohibition applies even if the father has only undergone eirusin with his wife but has not yet undergone nisuin or had sexual relations with his wife.  (We discussed the two stages of the marriage ceremony earlier in our study.)

The rabbis legislated sh’ni’ot to extend this mitzvah as well.  They prohibit a man from having sexual relations with his maternal and paternal grandfathers’ wives, whether or not these women are his grandmothers.  They prohibited a man from having sexual relations with women married to his great-grandfathers up the paternal line but not up the maternal line.  The rabbis make this distinction because the mitzvah is primarily focused on a man’s father’s wife.  As with the sh’ni’ot in the prior mitzvah, it is hard to see how this would make much practical difference.

The punishment rubric here is the same as we saw for the prior two mitzvot.  The author says the prohibition applies to non-Jews, although a non-Jewish couple is not considered married until they have had sexual relations with each other.  As we saw previously, the sh’ni’ot do not apply to non-Jews.  The author does not mention a prohibition on the woman involved in this sexual relationship.  However, it would seem that both the man and woman involved in this sexual relationship would be guilty of adultery if the man’s father is still married to the wife.  That leads to a surprising outcome when it comes to the sh’ni’ot.  Take the example of the man’s grandfathers’ wives.  From the incest point of view, that sexual relationship is prohibited d’rabanan.  But if the grandfathers are still married to their wives, the relationship would also be adultery, and that is subject to the death penalty.

Mitzvah #192 prohibits a man from having sexual relations with his sister, a full sister or a half-sister either through his mother or through his father.  It forbids him from having sex with a sister whom his father sired by rape, or who was the product of an illicit relationship by either his mother or father.  There are no sh’ni’ot here, though.

Mitzvah #196 prohibits a man from having sexual relations with his father’s wife’s daughter but only if they have the same father.  Thus, if a man has intercourse with his half-sister, with whom he has a common father, and her mother is married to his father, he has broken two mitzvot. If a man has intercourse with his half-sister, with whom he has a common mother, he breaks only one mitzvah.  If a man has intercourse with his step-sister, that is a woman whose mother is married to his father but who has no common parent with the man, that is just fine.  The author is aware that mitzvah #192 already forbids any behavior forbidden by this mitzvah, and the author has no explanation.

  There is no death penalty for a Jewish man having sex with his sister.  Rather, the punishment for doing so b’mazid is karet even if there are witnesses and warning.  The punishment for doing so b’shogeg is a hattat.  The author does not mention the sister being punishable. 

The prohibition on having intercourse with one’s sister applies to non-Jews, but only with one’s sister from the same mother.  As we mentioned earlier, before DNA testing it was not possible to know paternity for sure.  The halachah assumes that in general if a married Jewish woman has a child, the child’s father is her husband.  The halachah normally does not assume the paternity of the child of a non-Jewish woman can be known for sure.

The author also adds to our knowledge of how mitzvot that apply to non-Jews might be enforced.  He says that a non-Jew who breaks any of those mitzvot is liable to the death penalty, even for breaking the mitzvah b’shogeg.  The non-Jew can be convicted on the testimony of two witnesses, Jewish or non-Jewish, or based on a confession.  The non-Jew need not be given a warning, though.  The purpose of a warning in criminal cases against Jews is to be sure that the defendant’s behavior was b’mazid, that the defendant knew exactly what he or she was doing and that it might have dire consequences.  Since non-Jews are punishable even if they act b’shogeg, the warning is not required.  All of this is the procedure if non-Jews are under the jurisdiction of a Jewish court.

            Mitzvot #193 and 194 prohibit a man from having sexual intercourse with his granddaughters.  Mitzvah #193 prohibits the relations with his son’s daughters, and mitzvah #194 prohibits the relations with his daughter’s daughters.  These prohibitions apply even if the son or daughter is the child of rape or another illicit relationship.  The rabbis extend this prohibition to great-granddaughters, but the rabbis disagree about whether these mitzvot extend down the generational chain.  The punishment is death or karet or a hattat or makkat mardut, as we have seen before.  The author does not mention any punishment for the women.

            Mitzvah #195 prohibits a man from having intercourse with his daughter. It applies to any daughter, even from an illicit relationship or a rape.  This mitzvah is unique in that there is no source verse in the Torah.  The rabbis derive the prohibition and its punishment using standard interpretive techniques, and the author explains their logic in detail.  He does not explain why the Torah did not simply prohibit this relationship.

            Deriving the prohibition is relatively easy.  The rabbis argue that if a man is prohibited from having intercourse with his granddaughters, the inference by kal v’homer shows he is also prohibited from having intercourse with his daughter.  But, as we have seen before, kal v’homer can be a source for prohibition but cannot be the source for punishment.  And the rabbis thought this behavior should be punishable. 

            The author quotes the Gemara to explain how we derive both the prohibition and its punishment by an inference technique called g’zairah shavah.  This technique can be the source for substantive rules and even punishments.  G’zairah shavah assumes that extra or unusual words that appear in more than once verse mean the topics the verses discuss have something in common.  The rabbis need a tradition for what the topics have in common.  It seems to me the author is explaining this Gemara here both to provide a source for the “missing” mitzvah and its punishment, and to help us begin to appreciate the technique of g’ziairah shavah.

            The author starts with the Gemara, which appears in Yevamot 3a and Chagigah 11b that asks how we know that a father may not have sex with his daughter and how we know the punishment is death by burning, “Rava said, ‘Rav Yitzhak ben Avdimi told me:  ‘We learn it from heinah, heinah. We learn if from zimah, zimah.’’”  This cryptic style is not atypical.  First we have to know what question the g’zairah shavah is being used to answer.  The Gemara here gives us the crucial terms that carry from one verse to the other.  We will have to identify the source verses and figure out how this g’zairah shavah relates the verses to each other.  Before we try to untangle this one, please look up Lev. 18:10, 18:17 and 20:14, and find the terms heinah and zimah where they appear.

            The first step is to determine how we know by g’zairah shavah that a man is prohibited from having sex with his daughter.  Lev. 18:10 explicitly prohibits a man from having sex with his granddaughters.  It ends with an apparently extra phrase, “ki ervat’cha heinah,” “because they are your [the man’s] ervah.”  The focus here is on the word heinah.  (There could, in theory, be some other interpretive technique that learns something from the rest of the phrase, given that the prohibition the verse articulates would be clear even without this added phrase.)  To make a g’zairah shavah work, we need to find the word heinah that appears in another verse, especially if it is also extra there.  Lev. 18:17 prohibits a man from having sex with a woman and also her daughter or granddaughters.  That verse ends with the apparently extra phrase, “sh’eirah heinah, zimah hi,” “they are close relatives, it is lewdness.”  The word heinah also appears in this extra phrase, so using the technique of g’zairah shavah, we can look for something about the rule described in this verse and carry that over to the topic of our prior verse.  (In theory, either verse could be the source of the rule we carry over to the topic of the other verse.  It is rabbinic tradition that tells us what rule to carry over and which direction it goes in.)  Here, our second verse prohibits a man from having sex with a woman, her daughter, and her granddaughters.  Our first verse prohibits a man from having sex with his granddaughters but leaves out his daughter.  The g’zairah shavah tell us that since a daughter is prohibited by the second verse, we should infer that a daughter is also prohibited in our first verse.  We infer that because the word heinah appears in an extra phrase in each verse.

            The next step is to derive the punishment for a man having sex with his daughter.  The Torah does not explicitly state what the punishment is for a man who has sex with his granddaughter.  The verse that prohibits a man from having sex with a woman and her daughter and/or granddaughters also does not list a punishment.  But Lev. 20:14 says that this latter offense is punishable by death by burning.  And that verse has an extra phrase at the end that includes the word zimah.  We already noted that the extra word zimah appears in the verse that prohibits a man from having sex with a woman and her daughter and/or granddaughters, and that the g’zairah shavah based on the word heinah allows us to learn rules about a man having sex with his daughter from the rules about a man having sex with a woman and her daughter and/or granddaughters.  That chain allows us to carry the punishment for the man having sex with a woman and her daughter and/or granddaughters over to the prohibition on a man having sex with his granddaughters and also to the prohibition on a man having sex with his daughter.  Hence, a man having sex with his daughter or granddaughter is punishable by death by burning.

            The author, in this essay, emphasizes the enormous power of the technique of g’zairah shavah.  It can be a source of prohibition; it can be a source of punishment, even the death penalty; and it can allow us to learn a whole array of rules about one topic from the rules of another topic.  But, just to remind us, it is a literary technique that relies on a tradition of validity.

            Rambam relies on the requirement that a g’zairah shavah have an ancient tradition to back it up to solve a problem he has with including the prohibition on a man having sex with his daughter in Rambam’s count of the 613 mitzvot.  One of Rambam’s principles for a mitzvah to count as one of the 613 is that it is explicitly mentioned in the Torah.  A prohibition learned by a literary technique the rabbis used to interpret the Torah would not be counted in the 613.   The prohibition on a man having sex with his daughter is not explicitly mentioned in the Torah, but Rambam counts it anyway, explaining that it is already in the Torah in the form of a g’zairah shavah, and that g’zairah shavah had been given to Mosheh.  That, Rambam thinks, is close enough.  The author cites Ramban, who does not find Rambam’s argument convincing.

            At the end of this essay, the author discusses other interactions between this mitzvah and the prohibition on a man having sex with a woman and her daughter or granddaughters.  Let’s save this material until we have a better understanding of that mitzvah.