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Issurei Bi'ah (Forbidden Sexual Relations)

ee-soo-RAY bee-AH

Jewish law defines a precise map of sexual relations that are forbidden, rooted in biblical law and elaborated across centuries.

At the heart of Jewish family law sits a detailed system—found first in the Torah (Leviticus 18 and 20)—that spells out which sexual relations are prohibited. This isn't simply a list of rules; it's a framework that shapes how Jewish communities understand marriage, family integrity, and ritual purity. The prohibitions include incestuous relations, relations during a woman's menstrual period (called niddah), relations with a married woman, and several other unions. Think of it like a legal architecture: the Torah gives the foundational categories, and later Jewish sages (especially Maimonides in his Mishneh Torah) built an entire interpretive edifice around them, clarifying boundaries, defining exceptions, and explaining the reasoning behind each restriction.

Over time, rabbinical interpreters didn't simply repeat the ancient rules—they re-read them, applied them to new situations, and wove them into a coherent philosophy of family, consent, and social order. The medieval codes (particularly the Shulchan Aruch's Even HaEzer section) refined and systematized these discussions into practical rulings that communities could follow. What makes this system distinctive is that it isn't arbitrary; each prohibition carries theological and social weight—protecting lineage, preserving the dignity of marriage, maintaining ritual separation, and upholding communal stability.

How it traveled

  1. Leviticus
    Eretz Yisrael (travels) · -1000
    explains
  2. Deuteronomy
    Eretz Yisrael (travels) · -1000
    explains
  3. Ezekiel
    Eretz Yisrael (travels) · -571
    explains
  4. Targum Jonathan on Leviticus
    · 30
    explains
  5. Targum Jonathan on Deuteronomy
    · 30
    explains
  6. Targum Jonathan on Exodus
    · 30
    explains
  7. Onkelos Leviticus
    · 80
    explains
  8. Onkelos Deuteronomy
    · 80
    explains
  9. Tosefta Yevamot
    · 190
    explains
  10. Tosefta Ketubot
    · 190
    explains
  11. Tosefta Kiddushin
    · 190
    explains
  12. Tosefta Gittin
    · 190
    explains
  13. Tosefta Sanhedrin
    · 190
    explains
  14. Tosefta Keritot
    · 190
    explains
  15. Mishnah Yevamot
    Yavneh · 200
    explains
  16. Mishnah Ketubot
    Yavneh · 200
    explains
  17. Mishnah Kiddushin
    Yavneh · 200
    explains
  18. Mishnah Keritot
    Yavneh · 200
    explains
  19. Mishnah Sotah
    Yavneh · 200
    explains
  20. Mishnah Gittin
    Yavneh · 200
    explains
  21. Mekhilta DeRabbi Shimon Ben Yochai
    · 200
    explains
  22. Mishnah Niddah
    Yavneh · 200
    explains
  23. Avot DeRabbi Natan, Recension B
    Yavneh · 220
    explains
  24. Sifra
    · 250
    explains
  25. Sifrei Devarim
    Eretz Yisrael (travels) · 250
    explains
  26. Mekhilta DeRabbi Yishmael
    Eretz Yisrael (travels) · 250
    explains
  27. Sifrei Bamidbar
    Eretz Yisrael (travels) · 250
    explains
  28. Jerusalem Talmud Yevamot
    Tiberias · 400
    explains
  29. Jerusalem Talmud Ketubot
    Tiberias · 400
    explains
  30. Jerusalem Talmud Sanhedrin
    Tiberias · 400
    explains

Key passages(20)

Deuteronomy · 1400 BCE

Very high

כִּֽי־יִמָּצֵ֨א אִ֜ישׁ שֹׁכֵ֣ב ׀ עִם־אִשָּׁ֣ה בְעֻֽלַת־בַּ֗עַל וּמֵ֙תוּ֙ גַּם־שְׁנֵיהֶ֔ם הָאִ֛ישׁ הַשֹּׁכֵ֥ב עִם־הָאִשָּׁ֖ה וְהָאִשָּׁ֑ה וּבִֽעַרְתָּ֥ הָרָ֖ע מִיִּשְׂרָאֵֽל׃ {ס} &nbsp

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Deuteronomy · 1400 BCE

Very high

אָר֗וּר שֹׁכֵב֙ עִם־אֲחֹת֔וֹ בַּת־אָבִ֖יו א֣וֹ בַת־אִמּ֑וֹ וְאָמַ֥ר כׇּל־הָעָ֖ם אָמֵֽן׃ {ס}        

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Deuteronomy · 1400 BCE

Very high

אָר֕וּר שֹׁכֵ֖ב עִם־חֹֽתַנְתּ֑וֹ וְאָמַ֥ר כׇּל־הָעָ֖ם אָמֵֽן׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֤ת בַּת־בִּנְךָ֙ א֣וֹ בַֽת־בִּתְּךָ֔ לֹ֥א תְגַלֶּ֖ה עֶרְוָתָ֑ן כִּ֥י עֶרְוָתְךָ֖ הֵֽנָּה׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֨ת בַּת־אֵ֤שֶׁת אָבִ֙יךָ֙ מוֹלֶ֣דֶת אָבִ֔יךָ אֲחוֹתְךָ֖ הִ֑וא לֹ֥א תְגַלֶּ֖ה עֶרְוָתָֽהּ׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֥ת אֲחוֹת־אָבִ֖יךָ לֹ֣א תְגַלֵּ֑ה שְׁאֵ֥ר אָבִ֖יךָ הִֽוא׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֥ת אֲחֽוֹת־אִמְּךָ֖ לֹ֣א תְגַלֵּ֑ה כִּֽי־שְׁאֵ֥ר אִמְּךָ֖ הִֽוא׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֥ת אֲחִֽי־אָבִ֖יךָ לֹ֣א תְגַלֵּ֑ה אֶל־אִשְׁתּוֹ֙ לֹ֣א תִקְרָ֔ב דֹּדָֽתְךָ֖ הִֽוא׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֥ת כַּלָּֽתְךָ֖ לֹ֣א תְגַלֵּ֑ה אֵ֤שֶׁת בִּנְךָ֙ הִ֔וא לֹ֥א תְגַלֶּ֖ה עֶרְוָתָֽהּ׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֥ת אֵֽשֶׁת־אָחִ֖יךָ לֹ֣א תְגַלֵּ֑ה עֶרְוַ֥ת אָחִ֖יךָ הִֽוא׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֥ת אִשָּׁ֛ה וּבִתָּ֖הּ לֹ֣א תְגַלֵּ֑ה אֶֽת־בַּת־בְּנָ֞הּ וְאֶת־בַּת־בִּתָּ֗הּ לֹ֤א תִקַּח֙ לְגַלּ֣וֹת עֶרְוָתָ֔הּ שַׁאֲרָ֥ה הֵ֖נָּה זִמָּ֥ה הִֽוא׃

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Leviticus · 1400 BCE

Very high

וּבְכׇל־בְּהֵמָ֛ה לֹא־תִתֵּ֥ן שְׁכׇבְתְּךָ֖ לְטׇמְאָה־בָ֑הּ וְאִשָּׁ֗ה לֹֽא־תַעֲמֹ֞ד לִפְנֵ֧י בְהֵמָ֛ה לְרִבְעָ֖הּ תֶּ֥בֶל הֽוּא׃

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Leviticus · 1400 BCE

Very high

אִ֥ישׁ אִישׁ֙ אֶל־כׇּל־שְׁאֵ֣ר בְּשָׂר֔וֹ לֹ֥א תִקְרְב֖וּ לְגַלּ֣וֹת עֶרְוָ֑ה אֲנִ֖י יְהֹוָֽה׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֥ת אָבִ֛יךָ וְעֶרְוַ֥ת אִמְּךָ֖ לֹ֣א תְגַלֵּ֑ה אִמְּךָ֣ הִ֔וא לֹ֥א תְגַלֶּ֖ה עֶרְוָתָֽהּ׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֥ת אֵֽשֶׁת־אָבִ֖יךָ לֹ֣א תְגַלֵּ֑ה עֶרְוַ֥ת אָבִ֖יךָ הִֽוא׃ {ס}        

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Leviticus · 1400 BCE

Very high

עֶרְוַ֨ת אֲחֽוֹתְךָ֤ בַת־אָבִ֙יךָ֙ א֣וֹ בַת־אִמֶּ֔ךָ מוֹלֶ֣דֶת בַּ֔יִת א֖וֹ מוֹלֶ֣דֶת ח֑וּץ לֹ֥א תְגַלֶּ֖ה עֶרְוָתָֽן׃ {ס}        

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Leviticus · 1400 BCE

Very high

וְאִ֗ישׁ אֲשֶׁ֤ר יִשְׁכַּב֙ אֶת־אֵ֣שֶׁת אָבִ֔יו עֶרְוַ֥ת אָבִ֖יו גִּלָּ֑ה מֽוֹת־יוּמְת֥וּ שְׁנֵיהֶ֖ם דְּמֵיהֶ֥ם בָּֽם׃

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Leviticus · 1400 BCE

Very high

וְאִ֗ישׁ אֲשֶׁ֤ר יִשְׁכַּב֙ אֶת־כַּלָּת֔וֹ מ֥וֹת יוּמְת֖וּ שְׁנֵיהֶ֑ם תֶּ֥בֶל עָשׂ֖וּ דְּמֵיהֶ֥ם בָּֽם׃

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Leviticus · 1400 BCE

Very high

וְאִ֗ישׁ אֲשֶׁ֨ר יִשְׁכַּ֤ב אֶת־זָכָר֙ מִשְׁכְּבֵ֣י אִשָּׁ֔ה תּוֹעֵבָ֥ה עָשׂ֖וּ שְׁנֵיהֶ֑ם מ֥וֹת יוּמָ֖תוּ דְּמֵיהֶ֥ם בָּֽם׃

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Leviticus · 1400 BCE

Very high

וְאִ֗ישׁ אֲשֶׁ֨ר יִקַּ֧ח אֶת־אִשָּׁ֛ה וְאֶת־אִמָּ֖הּ זִמָּ֣ה הִ֑וא בָּאֵ֞שׁ יִשְׂרְפ֤וּ אֹתוֹ֙ וְאֶתְהֶ֔ן וְלֹא־תִהְיֶ֥ה זִמָּ֖ה בְּתוֹכְכֶֽם׃

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