Halakhah for Eruvin 191:3

There are women who are not meticulous about the laws of tzni’ut and many other mitzvot, but they wish to boast by wearing talit and tefilin. One should object to their agenda of turning the Torah and mitzvot into a site of social conflicts, as mitzvot should be performed for God’s sake, not as a tool to advance interests of one sort or another.¹The mishna on Berakhot 20a states that women are exempt from tefilin but does not clarify whether women who want to wear tefilin may do so just as they may perform other positive time-bound mitzvot like lulav and shofar. Eruvin 96a cites a beraita that states that Michal, the daughter of King Shaul, wore tefilin and that the Sages did not object. Tosafot (ad loc.) state in the name of Pesikta that the Sages indeed objected. Similarly, y. Berakhot 2:3 first cites an anonymous opinion that the Sages did not object and then cites R. Ḥizkiya to the effect that the Sages did, in fact, object. Tosafot state that according to the opinion that the Sages objected even though they did not object to women performing other time-bound positive mitzvot, it is because “tefilin require a clean body, and women are not zealously careful.” (It seems that the concern is that they may not wear tefilin while menstruating – see Rema 88:1 – and since they do not normally study laws that do not pertain to their obligations, they will not be careful about this. Perhaps there is also concern that they will handle a soiled diaper or another filthy household item.) Kol Bo also states in the name of Maharam that one should object to women who wish to wear tefilin because “they do not know how to keep themselves clean.” Beit Yosef cites this, and SA 38:3 rules: “Women and slaves are exempt from tefilin as it is a time-bound positive mitzva. Rema: If women wish to be stringent upon themselves, we object (Kol Bo).”
MA explains that if women had been obligated by the Torah to wear tefilin, the rationale that they are not careful about cleanliness would not exempt them from the mitzva. However, since they are exempt and there is a concern about cleanliness, their wearing tefilin is objectionable. Along these lines, AHS states that really men have the same problem; tefilin require a clean body. However, since men are obligated, they wear tefilin for Shema and prayers while being as careful as possible. Women, though, are exempt, and should not subject themselves to this serious concern. For them, the time of prayer and reciting Shema are the equivalent of the rest of the day for men. We therefore do not allow them to wear tefilin. Even though Michal wore tefilin and the Sages did not object, this case is not instructive. Presumably, they knew that she was completely righteous and knew how to take the proper precautions. Similarly, Kaf Ha-ḥayim 38:9 states in the name of Birkei Yosef and other Aḥaronim that one should object to women wearing tefilin and cites esoteric reasons for this as well.
Yet there are Rishonim who say that one should not object. Indeed, Orḥot Ḥayim challenges Maharam’s strict ruling (cited in Kol Bo) based on the opinion that the Sages did not object to Michal wearing tefilin. This is cited in Beit Yosef, which answers that Kol Bo relied on the view that the Sages indeed object to Michal. Olat Tamid (an early commentary on Shulḥan Arukh) 38:3 rejects Maharam’s view: if the prohibition on women wearing tefilin is based on cleanliness, why does Berakhot 20a state that they are exempt because it is a time-bound positive mitzva? Moreover, Michal wore tefilin and the Sages did not object. Therefore, Olat Tamid concludes: “We do not object to an old woman who we know is capable of guarding herself, and it is sort of case that they are discussing there [ in reference to Michal.” It is also said of several righteous women from early and later generations – including the wife of R. Ḥayim ibn Atar – that they wore tefilin.
The practical ruling is that a woman should not wear tefilin, and many authorities – including Rema, Kaf Ha-ḥayim, MB, and many others – state that objections should be raised against women who wish to wear tefilin. Nevertheless, a woman who wishes to wear tefilin has authorities to rely upon – Orḥot Ḥayim and Olat Tamid – and AHS also concludes that one should not object to one who is renowned as a righteous woman. Therefore, in practice, one should not object to this practice. However, a woman who wear tefilin should take care not to wear them while menstruating (though she may wear tefilin while counting her clean days) and should make sure to wear them in private, so that it is clear that she is wearing them for God’s sake and so that she does not advertise when she is menstruating.

In this prevention of wine libations, both Rambam (in Sefer HaMitzvot LaRambam, Mitzvot Lo Taase 194), may his memory be blessed, and Ramban (in his gloss to the Sefer HaMitzvot), may his memory be blessed, conceded that there is a negative commandment in this and that it is counted in the tally of the negative commandments. However they did disagree about it in the [following] matter: that Rambam extracts the prohibition of wine libations from the verse that is written in Parshat Haazinu (Deuteronomy 32:38), "drank the wine of their libations"; and the prohibition of other gifts to idolatry from, "Nothing is to cling to your hand from the anathema"(Deuteronomy 13:18) and from "You shall not bring an abomination" (Deuteronomy 7:26); [whereas] Ramban, may his memory be blessed, wrote that we learn the prohibition of all of the gifts of idolatry from this verse of "Guard yourself," and wine libations are included. And I have written this verse, like his opinion - not like my custom in all of the book, as I have written all [of the other verses] according to the opinion of Rambam, may his memory be blessed. But in this [case] I saw that this verse is very fit to expound the matter from it; and also that there is a warning in it. And [it is] as they, may their memory be blessed, said (Eruvin 96a), [that] every place where it states, "guard yourself," or "lest" or "do not," it is nothing but a negative commandment. However in the verse, "drank the wine of their libations," there is no warning. And I also saw great ones from the enumerators of the commandment that wrote like this.

To not nullify the guarding of the Temple: To not nullify the guarding of the Temple, [but rather] to always walk around it every night, as it is stated (Numbers 18:5), "And you shall guard the guarding of the Holy." And it is well-known that the expression of guarding takes the place of a negative commandment. And [it is] as they, may their memory be blessed, said (Eruvin 96a), "Every place in which it is stated, 'guard yourself,' 'lest,' and 'not,' is nothing but a negative commandment." And they said in Mekhilta, "'And they shall guard the guarding of the Tent of Meeting' (Numbers 18:4), - I only [know of] a positive commandment. From where [do I know] a negative commandment? [Hence], we learn to say, 'And you shall guard the guarding of the Holy.'" To here [are the words of Mekhilta]. And maybe they expounded a positive commandment and a negative commandment when they found two verses teaching one thing. And from the one that comes by way of a command in second person, they learned a negative commandment; and they expounded the command in third person - which is lighter than it - about a positive commandment. And anyone who weighs the things in just scales will concede about this - that the third person is lighter than a command in second person.

To not eat forbidden mixtures of the vineyard: That we are forbidden from eating forbidden mixtures of the vineyard only. And we have already explained in the previous commandment what forbidden mixtures of the vineyard are. And about this is it stated (Deuteronomy 22:9), "lest it be set aside (tikdash), the crop, the seed that you planted and the produce of the vineyard." - and they, may their memory be blessed, explained (Kiddushin 56b), "Lest it be incinerated by fire (tukad esh)," which is to say that it is not fitting that there be a purpose [from it], as it should all be forbidden in benefit. And the proof that there is a negative commandment in it, is that it is written in its prevention, "lest (pen)." And they, may their memory be blessed, said (Eruvin 96a) that in every place that it states, "guard yourself," "lest," and "do not" (heeshamer, pen ve-al), it is certainly a negative commandment.