Komentarz do Nidda 4:9

בנות כותים נדות מעריסתן – from their youth, when they are placed in the cradle, the Rabbis decreed concerning them that they defile on account of being menstruating women, as it is written (Leviticus 15:19): “When a woman has a discharge”/ואשה כי-תהיה זבה. And it is taught in a Baraita: I do not have [from this verse] anything other than a woman when she is an adult, from where do I learn that a baby one-day old is a menstruant woman? The inference teaches us: "ואשה"/when a woman. But the Cutheans (i.e., Samaritans) do not expound upon [the difference between]"אשה" "ואשה" - a woman, when a woman, for when they see them as minors (i.e., babies), they do not separate/set them aside, therefore, the Rabbis decreed concerning it that all of them [at whatever age] defile.

Introduction The first three mishnayot of chapter four deal with the menstrual impurity of women from three groups that were considered outside of the Jewish fold, as determined by the rabbis: Samaritans, Sadducees and Gentiles.

מטמאין משכב התחתון כעליון (they convey uncleanness to a couch beneath as to a cover above-see also Tractate Kelim, Chapter 1, Mishnah 3) – what is below that of someone who has sexual intercourse with a menstruating woman is unclean/impure just as that which is above a person with gonorrhea/זב, that just as what is above a person with gonorrhea does not defile anything other than foods and liquids, even that which is below the person having sexual intercourse with a menstruating woman does not defile anything other than foods and liquids. And that which is above the person with gonorrhea is that which is removed from upon the person with gonorrhea, we derive from Scripture that he does not defile a person and/or utensils but only food and liquids, as it is written (Leviticus 15:10): “whomever touches anything that was under him shall be impure [until evening],” what is תחתיו/under him? If you were to say that which is underneath the person with gonorrhea/זב – he derives from everything that he would touch when lying down, but the person who comes in contact with anything where the person with gonorrhea is below him becomes defiled, and since we do not combine them and write, “and anyone who comes in contact with everything that is below him and who carries them should wash his clothing,” and we make the religious ruling concerning him that he defiles, it follows that this, “and he defiles,” does not speak of people and utensils, but rather [only] foods and liquids. But Cutheans who engage in having sexual relationships with menstruating women, defile food and liquids that are lying underneath them , but not humans or utensils, like as to a cover above of a person with gonorrhea that he also defiles food and liquids but not a person or utensils. And all of these things were not stated other than at the time when the Cutheans uphold the Torah and are punctilious in many of the commandments like Israelites. But after they (i.e., the Rabbis) examined and found with them [things] like the image of a pigeon at the top of Mount Gerizim that they worship, they made them like complete heathens for all of their things, whether for matters of [ritual] impurity and purity or for the rest of the laws of the Torah, there is no difference between them and between heathens at all.

The daughters of the Samaritans are regarded as menstruants from their cradle. The Samaritans separated from the other Jewish communities (those whose center of worship was Jerusalem, the Samaritan center of worship was in Shechem) at a pretty early period in history, probably sometime during the first Temple period. As we shall see in section two, they did observe the laws of menstruation, but not according to rabbinic interpretation. One thing they did not believe was that young girls could become menstruants (we shall see in chapter five that the rabbis believed that they could). Therefore, all Samaritan girls had to be considered menstruants from the time they were born.

והן יושבות על כל דם (continue unclean for any sort of blood) – meaning to say, therefore, the Cuthians engage in sexual intercourse with menstruating women, therefore, they continue [to be] unclean for any sort of blood, for all blood that she sees, whether red whether green, she continues unclean for it the days of the menstruant woman, and this is a snare/stumbling block for them, that if she sees green blood today, she begins to count from today seven days of menstrual uncleanness , but if she sees during those actual days of menstrual uncleanness red blood, she does not count other than from the first sighting, but that blood was pure, and from the second sighting she needs to count.

And Samaritans impart uncleanness to a couch underneath as to a cover above, since they have intercourse with menstruants, because [their wives] sit [unclean for seven days] on account of any blood. The problem with Samaritan practice is not that they ignore the laws of niddah. They just observe them in the wrong way. Samaritan women treat all blood as if it were menstrual blood and they sit seven unclean days for any blood flow. If the blood that flowed on the first day was not actually menstrual and then the woman bled blood a subsequent day, she would treat that blood as if it was the continuation of her menstruation and she would go to the mikveh after seven days [Remember, according to the Torah one is impure for seven days after menstruation begins, even if it continues for several days]. According to rabbinic law, she should have begun the count only when actual menstrual blood began. Going to the mikveh too early will be ineffective (according to rabbinic law). Thus, Samaritan women will always be unclean. The men who have relations with them are also unclean and they will always defile any number of cushions upon which they sit, which is the rule concerning one who has relations with a menstruant (see Kelim 1:3). We should note that by declaring all Samaritans impure from birth, the rabbis were able to distance themselves from them. This in my opinion is probably a strong part of the reason for the laws of this mishnah. The rabbis are using the laws of niddah to distance Samaritans from mingling with their community. However, we should also note that simultaneously the Mishnah defines Samaritans as Jews, at least in a genetic sense. Mishnah three deals with Gentiles, and Samaritans are not considered Gentiles.

ואין חייבין עליהן - a person who wears or covers [himself] with those clothing and enters into the Sanctuary, is exempt from a sacrifice. Or if those clothing of their couch came in contact with heave-offering, we suspend them.

However, on account of their [uncleanness] no obligation is incurred for entrance into the Temple nor is terumah burned on their account, since their uncleanness is only of a doubtful nature. However, it is not certain that all Samirtan women (and men) are unclean, since the women do go to the mikveh. It is theoretically possible that they went to the mikveh on the correct day. Therefore, they only defile due to doubt. If a rabbinic Jew is defiled by contact with a Samaritan, and then he enters the Temple, he is not liable for entering the Temple while impure. If he touches terumah, the terumah is not burned (although it may not be eaten). These two rules always apply in cases of doubtful terumah.

מפני שטומאתן ספק – for we don’t know if she is a menstruating woman or not. But in the Gemara (Tractate Niddah 33b) it raises an objection on our Mishnah from that which is taught inTractate Tohorot, Chapter 4 (Mishnah 5): “On account of six matters of doubt do they burn the heave-offering,” [and one of them is] “because of a doubt concerning the clothing of a common, uneducated person [who is not punctilious in the observance of the laws of ritual purity],” that is to say on the clothing of a common, uneducated person if they came in contact with it (i.e., heave-offering), it is burned, because perhaps it was [ritually] impure, and this Cuthean also, we derive it that if his couch came in contact with heave-offering, it would be burned, because he is a common, uneducated person, and he has the clothing of a common, uneducated person. And it (i.e., the Talmud) responds that our Mishnah speaks regards a Cuthean who immersed [in a ritual bath] in our presence and came up [from the Mikveh] and tread upon the clothing of a member of the group dedicated to the precise observance of the Mitzvot (i.e., a חבר) who is naked, or that he wore the clothing of a member of the group dedicated to the precise observance of the Mitzvot, or immersed his clothing in his presence (i.e., of the member of the group dedicated to the precise observance of the Mitzvot) in a manner whereby the clothing of the Cuthean when they are trodden upon [from a person with gonorrhea immediate treading, leaning against] did not come in contact with the clothing of the member of the group dedicated to the precise observance of the Mitzvot when he treated upon him, and afterwards, the clothing of the member of the group dedicated to the precise observance of the Mitzvot that the Cuthean tread upon them with heave-offering, we don’t burn the heave-offering on their account. For if it was because of the ritual impurity of the common, uneducated person, he would immerse himself. But if it was because of someone engaging in sexual intercourse with a menstruating woman, perhaps he did not engage in close sexual contact, and the days of his [ritual] impurity had already passed and the ritual immersion is effective. But if you wish to say that he engaged in close sexual contact, perhaps his wife was not continuing unclean for any sort of blood, but rather only on pure blood, and this is a compound uncertainty, and we on a compound uncertainty, we don’t burn the heave-offering.

פירשו ללכת בדרכי ישראל הרי הן כישראליות – but undefined, they are like Cuthean women.

Introduction Today's mishnah deals with Sadducean women. The Sadducees were one of the main factions during the Second Temple period. They were the rivals of the Pharisees, the group that the rabbis considered themselves to be the descendents of. Truth be told, we don't know a lot about the Sadducees because they left no historical record. The only information we know about them was written either by Josephus, the New Testament or the rabbis. In addition, many scholars believe that the Dead Sea Sect Jews were a splinter Sadducean group, although this is far from certain.

ר' יוסי אומר לעולם הן כישראל – but undefined, they are like Israelite women. But the Halakha is not according to Rabbi Yossi.

The daughters of the Sadducees, so long as they are accustomed to walking in the paths of their fathers, are to be regarded as Samaritan women. If they left those paths to walk in the paths of Israel, they are to be regarded as Israelite women. The mishnah basically accepts Sadducean women but disqualifies their ancestry. If Sadducean women observe Sadducean halakhah then they must always be regarded as niddot (menstruants), just as are Samaritan women. They will always defile the things that they touch and it will always be prohibited for Jewish men to have relations with them. However, the mishnah gives them more of an opportunity to join the remainder (meaning Pharisaic/rabbinic) Jews than it did for Samaritan women. All they must do is leave the path of their ancestors and "walk in the paths of Israel" and they are to be considered as regular Israelite women. Clearly this means that they must observe halakhah as the rabbis determine it. We should note that in this mishnah "Samaritan" has become a code word for a genetic Jew who does not observe rabbinic halakhah. A Sadducean woman cannot be a Gentile because she is genetically Jewish. But when the mishnah wants to say that she is outside the rabbinic fold, it calls her a Samaritan.

Rabbi Yose says: they are always regarded as Israelite women unless they leave the paths of Israel to walk in the paths of their fathers. Rabbi Yose says that the a priori assumption about Sadducean women is that they have left the path of their fathers and act like (rabbinic) Jews. This is probably testimony to the weakness of the Sadducean faction after the destruction of the Temple. The Sadducees were more of a Temple-based group than the Pharisees and they don’t seem to have coped very well with the destruction of the Temple. In Rabbi Yose's time, a woman of Sadducean descent can be assumed to be observing rabbinic halakhah.

דם מכרית וכו' בית שמאי מטהרין – but even though that [regarding] her spit and her urine, the School of Shammai agrees with the Sages that decreed upon them to be like those with gonorrhea for all their matters, even so, her blood is pure, for the Rabbis reserved for her that it would be a means of recognition of their Rabbinic [ritual] impurity, in order that they would not burn heave-offering or Holy Things upon them.

The blood of a Gentile and the clean blood of a metzoraat (a woman with scale: Bet Shammai declares clean. And Bet Hillel holds that it is like her spittle or her urine. The menstrual blood (or zivah blood, blood that flows when a woman is not supposed to be menstruating) of a Gentile is, according to Bet Shammai, pure. This is because the chapters in Leviticus that discuss this issue are addressed to "the children of Israel" (Leviticus 15:2). "Clean blood" is the blood that flows from a woman during the period after childbirth following her time of impurity. For a boy, she is impure for a week and then pure for 33 days and double that amount of time for a girl. According to Bet Shammai, even if the woman is a metzoraat, who is impure, her blood is pure during this period, just as the blood of any woman is pure during this period. Bet Hillel disagrees on both of these issues. Concerning the blood of Gentile women, while Bet Hillel agrees that it is not impure by virtue of Torah law, they hold that the rabbis declared it impure (it would be impure derabanan). Just as they declared that other fluids that come from a Gentile's body are impure, urine and spittle, so too is their menstrual blood. This means that it defiles when moist, but not when dry, as do urine and spittle. Similarly, the rabbis hold that the "clean blood" of a metzoraat defiles like her spittle and urine when wet and not when dry. We could summarize the debate in the following way: Bet Shammai considers this blood not to be like the other fluids that come from the body, urine and spittle. Therefore, for both of these women, their urine and spittle can be impure while their blood is pure. Bet Hillel groups the blood with the other fluids, and just as urine and spittle are impure, so too is blood.

ודם טהור של מצורעת – but even though that the discharges of a woman leper such as her spit and urine are primary sources of ritual impurity like that of someone with gonorrhea, even so, her blood of purity (i.e., the vaginal bleeding experienced by a woman from eight to forty days after giving birth to a boy and from fifteen to eighty days after giving birth to a girl) is pure, for it is not a discharge, for we require that which is similar to spit (i.e., secretion of the mouth) which is formed in globules on being discharged (see Tractate Niddah 56a).

The blood of a woman after childbirth who did not immerse [in a mikveh]: Bet Shammai says it is like her spittle or her urine, But Bet Hillel says: it conveys uncleanness both when wet and when dry. Seven days after the birth of a boy and 14 days after the birth of a girl a woman is supposed to go to the mikveh, and subsequent blood will be pure. If she does not go to the mikveh, Bet Shammai says that this blood is like other liquids in her body it will defile when wet and not when dry. This is because she is still unclean, even though her blood is clean (i.e. the blood doesn't defile because it is blood, but rather because it is bodily fluid). Bet Hillel says that the blood is like menstrual blood i.e. it defiles because it is blood and not just because it is a fluid. This means that it will defile even when dry.

כרוקה וכמימי רגליה – that defile while moist but do not defile while dry. But this recognition is what is used regarding the blood of a heathen woman which defiles according to the Rabbis who decreed upon them that they would be like those with gonorrhea for all their matters, whereas the Israelite women (i.e., Jewish women) blood defiles moist and dry, and that of the heathen [which defiles] moist but not dry, like her spit and her urine that do not defile dry. But the blood of a woman leper also, even though her blood is not an issue/spring, she has the law of a spring upon her, for the All-Merciful included her from Scripture as it is written for a male, to include the leper to his discharge/issue and for the female, to include the female leper to her discharge/issue, and we state that her discharge/issue is suspicious, for if you wish you can say the rest of the discharges, we derive it from the male, and since we include the [male] leper to his discharges, we include the female leper with her discharges, for there is something analogous to it in the male, but to her blood, there is nothing [like it] in the male, for since the All-Merciful included her blood, that it would be like her spit and like her urine, if so, just as her spit and her urine defile moist and don’t defile when dry, so too her blood is like this.

They agree that if she gave birth while in zivah, it conveys uncleanness both when wet and when dry. Both houses agree that if she gave birth while in a state of zivah, meaning while she was impure due to non-menstrual blood, her blood defiles as would menstrual blood, until she goes to the mikveh, after seven days for a boy and 14 days for a girl. In other words, the fact that this is supposed to be "clean blood" does not get her out of the fact that she had unclean blood before she even gave birth.

דם היולדת- that passed the days of [ritual] defilement of a menstruant woman who did not immerse [as yet in the Mikveh].

בית שמאי אומרים כרוקה וכמימי רגליה - it defiles when moist but does not defile when dry. But even though it is blood of purity, the All-Merciful ties it to days but these were filled, but not to make it defiled also because of a discharge because it doesn’t form globules on being discharged, nevertheless, the Rabbis decreed [ritual] defilement upon her, for since she did not immerse [in a Mikveh], she is [ritually] impure/defiled, as a decree that after seven [days] is like within seven [days]. But however, it was not decreed that that it would be defiled [both] moist and dry like before the seven [days], for just as there is recognition that they knew that his defilement is according to the Rabbis.

ובית הלל אומרים מטמא לח ויבש – for his [ritual] impurity is from the Torah all the time that he didn’t immerse [in the Mikveh]. For the School of Hillel holds that the All-Merciful ties days and ritual immersion, all the while that she didn’t immerse, her blood after the seven [days] is like that of before the seven days.

ומודים ביולדת זוב – it at the time of her giving birth she had a flux, she would need to count seven clean days prior to becoming [ritually] pure, but if she gave birth and didn’t count [seven clean days], the School of Shammai agrees with the School of Hillel that her blood is impure moist and dry even though the seven days following her giving birth to a male had passed or two weeks for a female, for the blood of a woman with a flux always remains in its impurity from the Torah until she counts seven clean [days].

המקשה נדה – this is what it says: A woman having difficulties in her giving birth during the days of her menstruating period and saw blood during her labor, she is a menstruant woman/Niddah, for the Torah did not purify the blood of her protracted labor other than during the eleven days of her days of protracted menstruation/זיבה, but the All-Merciful did not purify it during her days of being a menstruant woman/נדה .

A woman who is having difficult labor is regarded as a menstruant. A woman who is having difficult, protracted labor and is bleeding, is considered to be a niddah. This seems a bit strange to us after all, a pregnant woman can't menstruate. But it is in reality a leniency that this blood is not considered to be blood of zivah (non-menstrual blood). If it were non-menstrual blood she would have to wait seven days in which she doesn't bleed to become clean. Since it is considered menstrual blood, she will be clean seven days after giving birth (for a boy, 14 for a girl).

קשתה- on account of the fetus for three days during the eleven days of her protracted menstruation/ימי זיבה, and she saw it (i.e., blood) for three consecutive days.

If she had difficult labor for three days of the eleven days and she ceased having pains for twenty-four hours and then gave birth, she is regarded as having given birth in zivah, the words of Rabbi Eliezer. Rabbi Joshua says: a night and a day, as the night and the day of Shabbat. The eleven days referred to here are the eleven days between menstrual periods in which any blood flow is considered to be zivah. This woman had difficult labor for three days, meaning she bled during a period of three days. Normally, this blood would be considered zivah, because it came not during the time when blood is considered menstrual. However, because she was in labor, we considered the blood to be menstrual blood, as we saw in section one. But then she ceased having pains. When she gives birth, we now can consider the blood to be zivah blood. In other words, since the pains stopped, the blood is considered to be zivah after all and not from the birth itself. Rabbi Eliezer says that the cessation of pain must be for 24 hours. Rabbi Joshua says that the cessation must be for a whole day like Shabbat, from night through the entire next day. A simple 24 hour cessation is not enough.

ושפתה (and she was relieved)- that she stood in relief and in comfort from her throes of birth agony for an astronomical period of twenty-four hours on the fourth day.

That she ceased from having pain, but not from bleeding. This section explains that the cessation is only from the pains of labor. The bleeding continues. If she were to stop bleeding as well and then give birth, she would not even be considered as having given birth from zivah. The blood that comes at childbirth would be from childbirth and she would be impure 7/14 as is always the case after childbirth.

וילדה (and she gave birth) – and the matter was revealed that the blood that she saw did not come on account of the fetus, therefore, this [woman] gives birth while having a flux. But if she did not have relief close to her giving birth, all of the blood that she saw, was on account of the fetus and the All-Merciful purified her from the blood of flux, as it is written (Leviticus 15:25): “When the woman had a discharge of blood/זוב דמה [for many days, not at the time of her menstrual impurity, she shall be impure, as though at the time of her menstrual impurity, as long as her discharge lasts],” her blood is on account of herself but not her blood on account of her fetus.

לילה ויום – that if she had relief for half of Tuesday and she gave birth during the middle of Wednesday, for she had a period of relief for an astronomical period of twenty-four hours, this is not comfort/relief, unless her relief was for a night and a day after the night,

like Friday night and its day. And the Halakha is according to Rabbi Eliezer.

ששפתה מן הצער – meaning to say, that she was relieved that we stated [in the Mishnah], that she had relief from the pain even though she didn’t have relief from the blood, it is relief.

כמה הוא קשויה – that she does not come to being a woman with a flux with all of the blood that she will see.

How long can protracted labor [be considered] as lasting? Today's mishnah asks how long we can consider a woman to be in protracted labor such that any blood flow is considered niddah and not zivah. Remember, this is a leniency, for if it were considered zivah, she would need to have seven clean days to become pure. The question is not empirical how long could a woman actually have protracted labor. The question is legal how long can we legally attribute the blood to being from labor and not blood of zivah?

אפילו ארבעים וחמשים יום – if she did not have one day of relief near the birth, she didn’t come to protracted menstruation, and she doesn’t give birth while being a woman in flux.

Rabbi Meir says: even forty or fifty days. Rabbi Meir says even forty, fifty days, which might mean that there is no limit whatsoever. Any time she has protracted labor, the blood is considered menstrual, as long as she didn't stop having the labor pains.

דיה חדשה – it is enough for her if the labor is purified in one month, that is during the ninth month [of pregnancy], for she gives birth while with a flux on account of three days during the eighth [month].

Rabbi Judah say: the [ninth] month suffices for her. Rabbi Judah says that blood during the entire ninth month of her pregnancy is considered menstrual and not zivah, as long as she is having labor pains along with it.

אין קשוי יותר שבתות -that she was not in labor and saw [blood] for three days prior to two weeks, and then had continuous hard labor all of the [two] weeks after that, this is a woman giving birth while in flux on account of the three days that came prior to the two weeks [of hard labor]. And the Halakha is according to Rabbi Yossi and Rabbi Shimon.

Rabbi Yose and Rabbi Shimon says: protracted labor is not for more than two weeks [before birth]. Rabbi Yose and Rabbi Shimon say that she can be considered to be in protracted labor only for the two weeks before birth. Blood before this period must be considered zivah blood.

המקשה בתוך שמונים של נקבה – as for example, that she engaged in sexual intercourse [after immersing in a Mikveh] fourteen days after giving birth [to a female] and became pregnant and then aborted [the fetus] within eighty days.

If a woman was in hard labor during the eighty days prescribed for the birth of a female, all kinds of blood that she may observe are clean, until the fetus is born. But Rabbi Eliezer holds them to be unclean. This mishnah discusses an unlikely scenario, but one that the rabbis found interesting (in a legal sort of way) and therefore, worthy of discussion. [This is frequently the case in rabbinic literature. The rabbis wish to discuss legally complex cases, not ones that actually happen most frequently]. A woman gave birth to a girl and then was impure for 14 days. After this time she went to the mikveh and then had relations with her husband (I know, a bit quick, but possible). She became pregnant and was already having pain and blood during the 66 day period in which the blood is considered pure. Note that she knows that this blood is from the new pregnancy, and not the old one. The rabbis hold that this blood is clean until she gives birth again. At this point, if we are sure it is a birth, then she will again be impure with birth uncleanness. Rabbi Eliezer says that since we know that this blood is not from the previous birth, in which case it would be clean, but rather from the difficult labor due to the subsequent birth, we must consider this blood to be unclean. She will have the uncleanness of a menstruant, as was the case in yesterday's mishnah.

כל דמים שהיא רואה טהורים – for all of it is within the completion [of her period of purification], which is the blood of purity.

They said to Rabbi Eliezer: if in a case where the law was stringent in regard to blood discharged in the absence of pain, it was nevertheless lenient in regard to blood discharged during hard labor, in a case where it was lenient in regard to blood discharged in the absence of pain is there not even more reason to be lenient in regard to blood discharged during hard labor? The rabbis now argue out their position. A woman who is pregnant and discharges blood but doesn't have any labor pains is considered a zavah. Her blood is not considered menstrual rather the greater stringency of zivah applies. Nevertheless, if she was in hard labor at the time, the blood would be considered birth blood, which would give her the status of a niddah and not a zavah. Therefore, in a case where the law is generally lenient, during the days of her purity (the 80 days after the birth of a girl), when all her blood is considered pure, so too we should be lenient with regard to blood that comes from labor pains. She should be a niddah and not a zavah.

ור' אליעזר מטמא – [she is defiled as] a menstruant woman/Niddah. For since it (i.e., the blood) came through hard labor, it is not the blood of purity, but rather on account of the fetus that is in her womb. But the All-Merciful (i.e., God) purifies it from her being in flux on account of her labor, but not from being a menstruant woman.

He replied: it is enough for the case inferred to be treated in the same manner as the one from which it is inferred. For in what way were you lenient upon her? From the uncleanness of a zivah, but she does have the uncleanness of a niddah. Rabbi Eliezer responds that this doesn't make sense. The leniency during pregnancy was that she was not a zavah she was only a niddah. So when we derive a law from this situation, we don't need to say that she is pure. It is enough to say that the derived status is the same as that from which it derived. Just as her blood had the status of niddah during her pregnancy, so too during the 80 days of purity, blood due to hard labor has the status of niddah.

שהחמיר בדם השופי - as for example, the other women giving birth who see three days of relief and then gave birth, is a woman who gives birth with a flux.

היקל בדם הקושי – to purify her from her flux.

מקום שהיקל בדם השופי – to purify her from all defilement, as for example, within her completion [of the period of purification].

אינו דין שנקל בדם הקושי – to purify the blood from all defilements and even from being a menstruating woman.

דיו לבא מן הדין [להיות כנדון] – as for example the labor that is within the completion that [of the period of purification following the birth of a child] that you learn from the undefined period of labor, it is enough to be like that which is judged to be like an undefined period of labor, for just as an undefined period of labor – the woman is defiled as a menstruating woman, so the labor that is within the completion [of that period of purification following the birth of a child] is defiled with the status of being a menstruating woman/Niddah.

כל אחד עשר יום – after the seven days of menstruation/Niddah.

Throughout all the eleven days a woman is in a presumption of cleanness. If she did not examine herself if this was unwittingly, under duress or intentionally, she is clean. Between one period and the next there are eleven days during which a woman can presume that she will not menstruate (according to the rabbis don't take this as gynecological advice). During this period there is a legal presumption that she is clean. If she doesn't examine herself for any reason, even intentionally, she is still clean.

בחזקת טהרה – and she doesn’t have to examine herself, for it is a Halakha transmitted to Moses at Sinai (albeit not written down) that there is no distinction between one menstruating cycle to another that is less than eleven days.

If the time of her regular period arrived and she did not examine herself she is unclean. When her period is supposed to arrive, she loses her presumption of cleanness. She must examine herself, and if she does not, she is considered impure.

ישבה לה ולא בקדה – our Mishnah is deficient and should be read as follows: During the days of her menstruating period it requires examination. If she sat and did not examine herself inadvertently, or she was under constraint, or willfully didn’t examine herself, she is [ritually] pure/clean.

Rabbi Meir says: if a woman was in a hiding place when the time of her regular period arrived and she didn't examine herself she is clean, because fear suspends the flow of blood. Rabbi Meir holds that fear will suspend the onset of a woman's period. Therefore, if a woman is in hiding, perhaps due to war, and the time of her period arrives, she remains pure because we can assume that she did not have her period.

הגיעה שעת וסתה ולא בדקה – even though she examined herself afterwards and found herself to be pure/clean, since she didn’t examine herself at the time of her period, that she is impure/unclean, for her menstruation comes at its [appropriate] time.

But during the days prescribed for a zav or a zavah or for one who waits day against day, these are presumed to be unclean. A woman who has three consecutive days of blood discharge not during the time of her period is a zavah. A man who has non-seminal genital discharge for three straight days is a zav. Both of them must check themselves every day. Every day that they do not, they are under the presumption of being impure. "One who waits day against day" refers to a man or woman who had a genital discharge that is not menstrual or semen for one or two days (on the third day they would become a zav/zavah). They too must check themselves every day to see if more discharge had occurred. If they do not check themselves, they are presumed unclean. To sum up the entire mishnah if there is some sign that would make us assume that she/he would menstruate or have impure discharge, then there is no presumption of cleanness. Without checking, she/he is impure.

במחבא (in hiding) – on account of robbers or an army that comes came to the city. But the Halakha is not according to Rabbi Meir.

אבל ימי הזב והזבה – the seven clean days that she needs to count.

ושומרת יום – as for example, that she sees [blood] one day or two days during the days of her flux, she does not count other than one day in cleanliness and she ritually immerses [herself] in the evening and is pure/clean to her husband.

הרי אלו בחזקת טומאה – since her fountain was opened up and she saw it (i.e., blood) today, even though it is within the eleven [days], she is on the morrow in the presumption of impurity/uncleanness.