Halakhah su Levitico 15:31

That He prohibited any impure person from entering the Sanctuary (the Tabernacle) - and everything that is similar to it for [all] the generations: All of the courtyard and from the Gate of Nikanor onwards, which is the courtyard of the Israelites. And that is His, may He be exalted, saying, "so that they shall not render their camp impure" (Numbers 5:3). And in the Gemara, Makkot (Makkot 14b), they said, "One who entered the Temple [while] impure - a punishment is written and a prohibition is written: The punishment - 'he has rendered impure the Tabernacle of the Lord, and that soul shall be excised' (Numbers 19:13). The prohibition - 'so that they shall not render their camp impure.'" And in the Mekhilta: "'Command the Children of Israel to send away from the camp' - is with a positive commandment. But from where [do we know] it is [also] with a negative commandment? You can say, 'so that they shall not render their camp impure.'" And the prohibition about this content has already been repeated with different language; and that His, may He be exalted, saying about a woman who has given birth, "and she shall not come into the sanctuary" (Leviticus 12:4). And in the [Sifra] (Sifra, Tazria Parashat Yoledet, Section 1:1), they said, "Because it is stated (Leviticus 15:31), 'And you shall separate the Children of Israel,' I would understand - whether [one enters] from its front or from its back and he is impure, he is liable. [Hence] we learn to say, 'and she shall not come into the sanctuary.'"And there it is explained that the law of a woman who has given birth and the law of other impure people is the same with regards to this. And they [also] said in the [Sifra] (Sifra, Acharei Mot, Chapter 12:13-14), about His saying "But if he does not wash and does not bathe his body" (Leviticus 17:16), "How is this? For [failure in] the bathing of his body, the punishment is excision, but for [failure in] the washing of his clothes, it is with forty [lashes]. And from where [do we know] that it is speaking here of his rendering the sanctuary and its consecrated objects impure? It prohibited and punished, etc." Behold it has been made clear that one who transgresses this negative commandment - if he was intentional, he is punished with excision; and if he was inadvertent, he must bring a variable offering, as we explained in Commandment 72 of the Positive Commandments. And the regulations of this commandment have already been explained at the beginning of Shevuot and in Horayot. (See Parashat Nasso; Mishneh Torah, Admission into the Sanctuary 3.)

And the laws of the measure of the stain (Niddah 58b), and in which case it is attributed to a stain [from something else] and in which case it is not attributed [to it]. And one who has a wound in that place, if she attributes it to it until the wound heals. And the matter of what is the law of a girl minor who has had intercourse and has blood flow from her (Niddah 64b). And the blood of virginity (breaking the hymen), that the Sages determined to be like menstrual blood (Niddah 65b). And the many laws of the regular times, and the law of separation before her regular time, which is the [menstrual] period - meaning to say that day or that night that she is accustomed to [experiencing blood] upon it - is forbidden for sexual relations. [This is] from that which it is written (Leviticus 15:31), "And you shall separate the Children of Israel from their impurity," and the epalanation came that they should separate from their wives before their regular times. But after the period of the regular time has passed [without blood], they are permitted in sexual relations. And the matter of the distancing from the wife that they, may their memory be blessed, commanded (Shabbat 11a) regarding the matter of menstruation, in order that a man not stumble in sin - and it is that a man should not eat with his menstruant wife from the same tray, nor pass a thing from his hand to her hand (Shabbat 13a), nor speak to her about things that often cause sin nor similar to these things.

That an impure person not enter the entire Temple: That any impure person is prevented from entering the entire Temple - the likeness of which in the [future] generations is all of the yard from Nikanor Gate and inwards, which is the beginning of the yard of the Israelites - as it is stated (Numbers 5:3), "and they will not render your camps impure" - meaning to say the camp of the Divine Presence. And the proof of this being among the negative commandments is that which they, may their memory be blessed, said in the Gemara (Makkot 14b), "One who enters the Temple while impure [is liable for excision], as both the punishment and the warning are written [in the Torah.] The punishment is written (Numbers 19:13) 'the Tabernacle of God he has defiled and he shall be cut off.' The warning is written (Numbers 5:3) 'and they will not render your camps impure.'" And they also said in the Mekhilta (Sifrei Zuta on Bamidbar 5:3), "'Command the Children of Israel, and they shall send from the camp' - [that is] a positive commandment. From where do we derive [the] negative commandment? Since it is written, 'and they will not render your camps impure.'" And they said in Sifra (Sifra, Tazria Parashat Yoledet, Section 1 1), "Since it is stated (Leviticus 15:31), 'And you shall separate the children of Israel from their uncleanliness[...],' I might understand, whether from its midst or from its back," meaning to say that one who approaches the Temple from its back while he is impure would be liable for excision; "it is, therefore, written in respect to a yoledet (a woman after childbirth) (Leviticus 12:4), 'and into the sanctuary she shall not come,'" meaning to say the expression of coming is only about one who enters from the front. And there it is elucidated that the law of a yoledet and the other [cases of] impurity are the same regarding this.