Halakhah su Levitico 12:4

And the conception of a female indicates coldness in the constitution of the female. And in coldness, excesses abound; and hence she needs two weeks for the cleansing of her body. And so did I find the matter after I wrote this [in] Ramban, may his memory be blessed, and these are his words (Ramban on Leviticus 12:4): "Because the constitution of the female is cold and wet, and the dampness in the womb of the mother is very great and cold. And therefore, she gave birth to a female. And hence she requires a big cleansing because of the multitude of dampness and the blood decaying in her and because of her coldness. And it is well-known that the cold sicknesses require a longer time to be cleansed than the hot ones." To here [are his words].

That one impure not eat consecrated foods: That one impure not eat consecrated foods until he immerses and his sun sets and - if he is an impure one that requires atonement - until he brings his atonement, as it is stated (Leviticus 12:4), "every consecrated thing shall he not touch." And the language of Sifra, Shemini Parashat Yoledet, Chapter 1:8, "'Every consecrated thing shall he not touch and to the sanctuary shall he not come' - just like the one who enters the sanctuary in impurity is punished excision, so too one who eats consecrated foods in impurity is punished excision." And we say in Makkot 14b, "'Every consecrated thing shall he not touch' is a warning for the eater. You say it is for the eater or is it only for the one who touches, etc.," as it is [found] there.

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.