וְעֶרְוַ֨ת אֲח֧וֹת אִמְּךָ֛ וַאֲח֥וֹת אָבִ֖יךָ לֹ֣א תְגַלֵּ֑ה כִּ֧י אֶת־שְׁאֵר֛וֹ הֶעֱרָ֖ה עֲוֺנָ֥ם יִשָּֽׂאוּ׃
La desnudez de la hermana de tu madre, ó de la hermana de tu padre, no descubrirás: por cuanto descubrió su parienta, su iniquidad llevarán.
Rabbeinu Bahya
איש איש אל כל שאר בשרו לא תקרבו, “any man shall not approach his close relative (with a view to sexual relations).” This verse expresses the Torah’s prohibition of incest. According to Nachmanides the following verses describe the type of relations-through blood or through marriage- which are included in this prohibition. The biological reason for this prohibition is presumed to be that children born from such incestuous unions have a limited life expectancy and are generally genetically deficient in some way. Seeing that the whole purpose of sexual relations is the creation of healthy children, cohabitation with the various categories of family members mentioned in this chapter is forbidden. This is the meaning of the words (chapter 20,19) כי את שארו הערה, “for he has revealed his blood-relationship,” i.e. the prohibition is due to the deficiencies in such blood-relationship.
Concerning the prohibition to have sexual intercourse with a woman while she is experiencing her monthly cycle, this proves further that prohibitions of marital relations are rooted in considerations of health, the chance of a viable fetus being produced from such sexual unions. Seeing that the fetus is formed out of the blood of the woman either in the main or completely, reproduction of the human species from menstrual blood is scientifically not possible; the fetus would not even be started if cohabitation occurred during that period.
What would Nachmanides have to say in respect of Deut. 23,2 where the Torah permits [by implication, Ed.] the person who suffers from crushed testicles, i.e. is unable to sire children, to marry a female convert or a female Gentile slave who has been freed by her master (and has converted)? Surely if the dominating reason of the עריות legislation were rooted in biological considerations these people should not be permitted to cohabit with a Jewess, even one who was not a natural born Jewess! This proves that sexual intercourse not designed to produce Jewish offspring is not necessarily forbidden. I will explain this in context when we come to the relevant verses (Deut. 23,2).
Concerning the prohibition to have sexual intercourse with a woman while she is experiencing her monthly cycle, this proves further that prohibitions of marital relations are rooted in considerations of health, the chance of a viable fetus being produced from such sexual unions. Seeing that the fetus is formed out of the blood of the woman either in the main or completely, reproduction of the human species from menstrual blood is scientifically not possible; the fetus would not even be started if cohabitation occurred during that period.
What would Nachmanides have to say in respect of Deut. 23,2 where the Torah permits [by implication, Ed.] the person who suffers from crushed testicles, i.e. is unable to sire children, to marry a female convert or a female Gentile slave who has been freed by her master (and has converted)? Surely if the dominating reason of the עריות legislation were rooted in biological considerations these people should not be permitted to cohabit with a Jewess, even one who was not a natural born Jewess! This proves that sexual intercourse not designed to produce Jewish offspring is not necessarily forbidden. I will explain this in context when we come to the relevant verses (Deut. 23,2).
Ramban
NONE OF YOU SHALL APPROACH TO ANY THAT IS NEAR OF KIN TO HIM, TO UNCOVER THEIR NAKEDNESS. The reason for the prohibition of sexual relationships with one’s near of kin is not expressly written [in the Torah]. The Rabbi [Moshe ben Maimon] wrote in the Moreh Nebuchim253Guide of the Perplexed III, 49. that [this law seeks to inculcate the lessons that] we should limit sexual intercourse, hold it in contempt, and perform it rarely. Now these women which Scripture has forbidden amongst the relatives of one’s wife are forbidden because they are constantly together with him in his house,254“For as a rule, the mother of the wife, her grandmother, daughter, granddaughter, and sister-in-law are often with her; the husband meets them always when he goes out, when he comes in, and when he is at his work” (ibid., Friedlander’s translation). Now “if we were allowed to marry any of them, and were only precluded from sexual intercourse with them without marriage, most people would constantly become guilty of misconduct with them. But as they are entirely forbidden to us … there is reason to expect that people will not seek it, and will not think of it” (ibid.). and the same applies to one’s own relatives [sisters, aunts, and the wife of one’s uncle], who are frequently with him and he is closeted together with them. A similar reason the Rabbi states for all forbidden relations. Now Rabbi Abraham ibn Ezra has already written255In the verse before us. likewise that since the passion of man’s heart is like that of the animals, it was impossible for Scripture to forbid all females, and therefore it prohibited only those that are available to him at all times. But this is a very weak reason, that Scripture should make a person liable to the punishment of excision in the case of these forbidden relations, just because they are sometimes found together with him, and at the same time permit a man to marry many women, even in the hundreds and thousands! And what harm would there be if a man would marry only his daughter, just as was permitted to the Noachides,256Sanhedrin 58 b. or marry two sisters as did our patriarch Jacob? A person also could not do better than to give his daughter in marriage to his elder son, and they would inherit his possessions and multiply and increase in his house, for He created not the earth a waste, He formed it to be inhabited!257Isaiah 45:18. We have no tradition as to [the reason of] this prohibition of forbidden relationships, but logically it would appear that there is in this matter one of the secrets of creation, which attaches to the soul and is part of the secret of the transmigration [of souls], to which we have already alluded.258Genesis 38:8 (Vol. I, pp. 469-470).
Know that sexual intercourse is held distant and in contempt in the Torah unless it is for the preservation of the human species, and therefore where there can be no offspring [such as in pederasty or carnal intercourse with beasts], it is forbidden. Similarly, where [the union is such that] the child born therefrom will not have a healthy existence, nor succeed from it, the Torah prohibited such a union. This is the sense of the expressions: el kol ‘sh’eir’ b’saro [literally: to any ‘flesh’ next to his flesh]; for he hath made naked ‘eth sh’eiro’259Further, 20:19. See Ramban on Exodus 21:9 (Vol. II, pp. 356-7), where he elaborates on the meaning of this word sh’eir. [literally: his flesh]. Thus the Torah forbade these marriages on account of sh’eir [i.e., because the forbidden relations constitute “flesh” next to one’s own], the term sh’eir being derived from the expression [in the verse], ‘hanish’ar’ (he that is left) in Zion, and he that remaineth in Jerusalem.260Isaiah 4:3. The term sh’eir denoting “flesh” or “relative” is something which “remains” with a person, as it is his own or next to his flesh. Hence Scripture states, they are ‘sha’arah’ (near kinswomen); it is lewdness,261Further, Verse 17. meaning to say, “these are not marriages, nor fit for such a relationship, for they will not succeed [in having healthy offspring, as explained above]; rather it is lewdness, mere thoughts of indecency.” Thus the forbidden relationships are included in “the statutes,” the laws which constitute “the decrees of the King.” Now a decree is an ordinance which originates in the knowledge of the King, Who is wise in the management of His kingdom, and it is He Who knows the need for and the benefit of the command that He ordained, and He does not tell it to anyone except to His wise counsellors.
Know that sexual intercourse is held distant and in contempt in the Torah unless it is for the preservation of the human species, and therefore where there can be no offspring [such as in pederasty or carnal intercourse with beasts], it is forbidden. Similarly, where [the union is such that] the child born therefrom will not have a healthy existence, nor succeed from it, the Torah prohibited such a union. This is the sense of the expressions: el kol ‘sh’eir’ b’saro [literally: to any ‘flesh’ next to his flesh]; for he hath made naked ‘eth sh’eiro’259Further, 20:19. See Ramban on Exodus 21:9 (Vol. II, pp. 356-7), where he elaborates on the meaning of this word sh’eir. [literally: his flesh]. Thus the Torah forbade these marriages on account of sh’eir [i.e., because the forbidden relations constitute “flesh” next to one’s own], the term sh’eir being derived from the expression [in the verse], ‘hanish’ar’ (he that is left) in Zion, and he that remaineth in Jerusalem.260Isaiah 4:3. The term sh’eir denoting “flesh” or “relative” is something which “remains” with a person, as it is his own or next to his flesh. Hence Scripture states, they are ‘sha’arah’ (near kinswomen); it is lewdness,261Further, Verse 17. meaning to say, “these are not marriages, nor fit for such a relationship, for they will not succeed [in having healthy offspring, as explained above]; rather it is lewdness, mere thoughts of indecency.” Thus the forbidden relationships are included in “the statutes,” the laws which constitute “the decrees of the King.” Now a decree is an ordinance which originates in the knowledge of the King, Who is wise in the management of His kingdom, and it is He Who knows the need for and the benefit of the command that He ordained, and He does not tell it to anyone except to His wise counsellors.