As we’ve often seen, the Talmud discusses intimate and potentially private dilemmas in the same tone it discusses everything else. Today’s daf is no exception. We’ve been discussing what to do if one enters the Temple while in a state of ritual impurity, or becomes impure while there. Analogously, the mishnah on 14b also taught:
If a man was engaging in intercourse with a ritually pure woman, and she experienced menstrual bleeding and said to him: “I have become impure,” and he immediately withdrew from her, he is liable to bring a sin-offering for engaging in intercourse with a menstruating woman, because his withdrawal from her is as pleasant to him as his entry.
Like entering the Temple in a state of impurity, having sex with a menstruating woman (niddah) is a prohibition that comes from the Torah: “Do not come near a woman during her menstrual period of impurity to uncover her nakedness.” (Leviticus 18:19) Also analogous, the punishment for intentional violation of this law is karet (spiritual excision). Those who observe this prohibition on sleeping with a menstruant often do so by taking multiple precautions, sleeping separately and even refraining from casual touch.
But we also worried about what happens if someone becomes impure while they are in the Temple and, similarly, the question now at hand is: What if a woman begins to menstruate while engaged in intercourse? In the Temple, the answer was to remove oneself as quickly as possible. But that’s not the answer in this case. The mishnah teaches, somewhat counter-intuitively, that the man who, mid-coitus, learns that his partner is menstruating, should not immediately withdraw — because he will experience pleasure. Rather, he should remain inside her until he becomes flaccid, then pull out. Interestingly, the rabbis privilege avoiding sexual pleasure in the presence of menstrual blood over reducing time spent in direct contact with it. This is because the prohibition is on having sex with someone in niddah, not being in contact with menstrual blood. While contact with menstrual blood renders one impure, people are not commanded to avoid all forms of impurity; many sources of impurity, such as menstruation, sex and childbirth, are either unavoidable or viewed as necessary and valuable. Therefore, the rabbis prefer the man remain in extended contact with the menstrual blood so as to avoid the basic nature of the prohibition on “having sex” with a menstruant, which includes the pleasurable act of withdrawing while erect.
Today’s daf investigates the details of this mishnah — whether we’re speaking of people familiar or unfamiliar with these laws, and whether in general one is liable for violating other sexual prohibitions if one is flaccid in the act — before returning to a startlingly basic question:
Rabbi Yonatan ben Yosei ben Lakonya asked Rabbi Shimon ben Yosei ben Lakonya: From where in the Torah is the prohibition concerning one who engages in intercourse with a menstruating woman derived?
Rabbi Shimon ben Yosei ben Lakonya took a clod of earth and threw it at him and said: The prohibition concerning one who engages in intercourse with a menstruating woman?! The verse (Leviticus 18:19) states: “Do not come near a woman during her menstrual period of impurity to uncover her nakedness”!
Rabbi Yonatan ben Yosei ben Lakonya asks a question so stunningly obvious that his colleague tosses dirt at him in frustration. Where do we derive the prohibition of sex with a menstruating woman? There’s no need to derive it, as there is a Torah verse that explicitly states it!
Assuming Rabbi Yonatan is not a complete ignoramus, the Gemara proceeds to reframe his question and then provide an answer:
Rather, from where do we derive the prohibition with regard to the case in the mishnah concerning one who was engaging in intercourse with a ritually pure woman, and she said to him: “I have become impure,” that he must not withdraw immediately?
Hizkiyya said: The verse states: “And if any man lies with her, and her menstrual flow shall be upon him …” (Leviticus 15:24), teaching that even at any time when she is menstruating, the prohibition shall be upon him.
Rabbi Yonatan, the Gemara charitably concludes, must have been asking about the source of this more obscure rule, that one must wait before withdrawing from a menstruant. The language of the verse brought by Hizkiyya is interpreted to mean that even when her blood is on him — i.e., if this occurs while they have sex — he is commanded with regard to his behavior.
The Gemara now further interrogates the ruling:
We found a source for a positive mitzvah; from where do we derive that immediate withdrawal is also subject to a prohibition? Rav Pappa said: The verse states: “Do not come near a woman during her menstrual period of impurity to uncover her nakedness” (Leviticus 18:19). “Do not come near (tikrav)” means also the opposite: You shall not withdraw, as it is written: “Those who say: Withdraw (kerav) to yourself, come not near to me, for I am holier than you.” (Isaiah 65:5)
In our mishnah, the Gemara concludes, the man is subject to two mitzvot: a positive mitzvah to remain inside the woman until he becomes flaccid, and a prohibition on withdrawing immediately while still erect. This halakhah engages with an improbable but not impossible question of what to do when a woman becomes a niddah while having intercourse. And as we’ve come to expect, the Gemara unashamedly discusses the ramifications of the situation, and grounds its conclusion in words of Torah.
Read all of Shevuot 18 on Sefaria.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on May 19, 2025. If you are interested in receiving the newsletter, sign up here.
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