Voluntary Performance

  • Deracheha Staff; Laurie Novick, Director
Click here to view an updated version of this shiur with additional features
on the Deracheha website.
 
Please share feedback with us here!
 

Permissibility

 
May a woman choose to perform a mitzva in which she is not obligated? Under what circumstances is this allowed?
 

● Why should anyone question voluntary performance? (See Appendix One.)

 
Our sages debate the permissibility of women's voluntary mitzva performance in the context of their discussion of semicha, leaning on a sacrifice.[1]
 
Vayikra 1:2,4 Speak to benei (lit. children of or sons of) Yisrael and say to them: A person from amongst you when he brings a sacrifice to God… and he shall lean his hand on the head of the burnt offering and it will be accepted for him, to atone for him.  
 
At the time of the Bet Ha-mikdash, a person bringing a sacrifice would lean his hands on the animal’s head just before it was slaughtered. This created a personal, physical connection between the person bringing the sacrifice and the sacrificial animal.
 
Women are exempt from semicha based on a midrashic understanding of the above-cited verses. The Talmud cites the midrash, which also debates whether women may perform semicha voluntarily.[2]
 
 
The midrash halacha deduces from the use of the term "benei Yisrael" that benot Yisrael, daughters of Israel, i.e. women, are not fully included in the command. According to Rabbi Yehuda, women may not lean on a sacrifice at all.  Rabbi Yosei and Rabbi Shimon agree that women are not obligated in semicha, but maintain that women may lean voluntarily. (We explore their viewpoint below.)
 

●Can't benei refer to sons and daughters? (See Appendix Two.)

 
Semicha is a positive commandment that is not time-bound.[3] However, the Talmud links the debate over semicha to the discussion of women’s blowing shofar – a positive, time-bound commandment from which women are exempt – making the ruling on semicha relevant to positive time-bound commandments.[4]
 
Rabbi Yehuda
 
RASHI'S EXPLANATION: Rashi explains that Rabbi Yehuda prohibits women from leaning on a sacrifice or blowing shofar because he thinks that a woman who performs these acts violates the prohibition of "bal tosif," adding to the commandments.[5] 
 
Rashi Rosh Ha-shana 33a s.v. Ha-nashim For they are completely exempt [from shofar] because it is a positive time-bound mitzva and when they blow there is [a violation of] bal tosif [adding to the mitzvot].
 
Typically, bal tosif refers to adding quantitatively to a mitzva, for example, by sitting in the sukka for an additional day or attaching an extra compartment to tefillin.  However, Rashi suggests here that bal tosif might also refer to performing an act that is not obligatory, while treating it as if it is.
 
TOSAFOT'S EXPLANATION: Tosafot present a different understanding of Rabbi Yehuda's position.  On their reading, Rabbi Yehuda usually permits women to perform mitzvot voluntarily, even when exempted.  He prohibits women's leaning on sacrifices and blowing the shofar for other reasons.
 
Tosafot Eiruvin 96a s.v. Michal…According to one who doesn't hold that women have permission [to voluntarily perform mitzvot from which exempted], it is not because it gives the appearance of adding on [to the mitzvot].  Rather because blowing [shofar] is a rabbinically prohibited labor [on the festival] and semicha, even with mere resting of the hand [on the animal], gives the appearance of [a violation of the prohibition of] avoda she-bekodeshim [labor with sanctified animals].
 
Tosafot explain that a person who leans on a sanctified animal when not required to do so appears to be doing avoda she-bekodeshim, labor with sanctified animals.  Avoda she-bekodeshim is prohibited on a Torah level, and appearing to do it is rabbinically prohibited. Rabbi Yehuda would similarly prohibit women from blowing shofar, because there is a rabbinic-level prohibition on blowing shofar on a festival when not commanded.[6]
 
According to Tosafot, unless there is a specific reason to prohibit a woman's voluntarily performing a particular mitzva, Rabbi Yehuda permits it. [7] That does not tell us whether or not Rabbi Yehuda sees any value in the act.
 

Rabbi Yosei and Rabbi Shimon

 
The halachic consensus is to follow Rabbi Yosei and Rabbi Shimon's position over Rabbi Yehuda's. Their position also appears in a parallel midrash halacha, alongside a related anecdote:[8]
 
Sifra, Dibura De-Nedava II 2:2 Rabbi Yosei and Rabbi Shimon say: Women lean [as a matter of] reshut. Rabbi Yosei said: Abba Elazar said to me: We had a calf for a peace offering, and we brought it out to the women's area, and the women leaned on it. Not because leaning is [the law] with women, but rather because of nachat ru'ach shel nashim [women's gratification].
 
Apparently, women in the Temple wanted to perform semicha, even though they were exempt from it. Rabbi Yosei and Rabbi Shimon maintain that women’s gratification, nachat ru’ach shel nashim, has independent value.  If we assume that they, too, might have been concerned about the appearance of performing avodah shebekodeshim when leaning on animals voluntarily, we can learn here that nachat ru'ach shel nashim supersedes that rabbinic prohibition.  On this view, Halacha takes women's feelings into account.
 
As we have seen, Rabbi Yosei and Rabbi Shimon permit a woman to perform semicha as a matter of reshut, permission. There are two main ways in which to understand reshut here (and in general).
 
I. The act has little or no objective halachic value.[9] Here, we would say that a woman receives personal emotional satisfaction, but her action is not a direct fulfillment of God’s will.
 
II. The voluntary act has objective halachic value. There are two major elements to a mitzva: the command and the mitzva act. Although the command element of the mitzva cannot be recreated, the mitzva act still has meaning as a fulfillment of God’s will. This is sometimes called reshut de-mitzva.[10]
 
Rav Yitzchak Ha-levi, one of Rashi's teachers, characterizes a woman’s voluntary performance of mitzvot as 'bringing herself into the yoke of the mitzva.' This phrasing suggests that voluntary performance is a mitzva act. At the same time, he holds that the act is fully optional.
 
Machzor Vitri 359 So ruled Rav Yitzchak Ha-levi, that they are not obligated and don’t need [to perform positive time-bound mitzvot]. But if they desire to bring themselves into the yoke of mitzva the permission is in her hand… for she is one who fulfills a mitzva.
 
Rav Yitzchak thus calls a woman who undertakes voluntary performance a "mekayyemet mitzva," one who fulfills a mitzva.
 
Ramban uses an even stronger formulation to describe a woman's performance of positive time-bound mitzvot:
 
Chiddushei Ha-Ramban to Kiddushin 31a For it is reshut de-mitzva, and God commanded this mitzva to men as an obligation, to women as optional.
 
According to Ramban, a woman is commanded in the mitzva. It's just that men receive the mitzva as an obligatory act to pursue, while women receive it as an optional act to fulfill.[11]
 
The view that a woman's voluntary mitzva performance has halachic value, and may even itself be considered fulfillment of a mitzva, predominates.[12] Ra'avya (Ashkenaz, 12th century) directly calls a woman's voluntary mitzva performance a mitzva.[13]
 
Ra'avya II Sukka 640 For albeit one who is commanded and performs [a mitzvah] is greater than one who [performs but] is not commanded, in any case it is a mitzva.
 

The Value of Volunteering

 
The Halacha generally permits a woman to perform mitzvot from which she is exempt – and recognizes these acts as halachically meaningful. How, though, does voluntary performance compare to commanded performance?
 
In the Talmud, Rav Yosef discusses this question from a personal perspective.
 
Bava Kama 87a Rav Yosef [who was blind] said: At first I would have said that were someone to say that the halacha is according to Rabbi Yehuda, who said a blind man is exempt from mitzvot, I would make a festive celebration for the sages.  For what reason? For I am not commanded and I perform mitzvot.  Now that I have heard this [teaching] of Rabbi Chanina, that Rabbi Chanina said, 'Greater is one who is commanded and does [a mitzva] than one who is not commanded and does [a mitzva],' were someone to say to me that the halacha is not according to Rabbi Yehuda, I would make a festive celebration for the sages.  For what reason?  That when I am commanded I have greater reward.
 
At first, Rav Yosef thought that if, as a blind man, he were exempt from mitzvot, it would work to his advantage.  Any initiative he took would be valued, while he would never be subject to punishment.  From Rabbi Chanina, however, Rav Yosef learns that it is greater to perform mitzvot as a response to a command than to do it voluntarily.  "Gadol ha-metzuveh ve-oseh mi-mi she-eino metzuveh ve'oseh." "Greater is one who is commanded and does than one who is not commanded and does."
 
Rabbi Chanina describes the commanded performer as "greater" than one not commanded, implying that the latter's act still has worth.  Rav Yosef expresses worth in terms of reward, where reward signifies the act’s halachic value. The reward for voluntary action is smaller, but there is still reward.
 
Why does one who is commanded receive greater reward? Voluntary performance is praiseworthy, for it indicates individual initiative in service of God. However, Ritva explains why performance of a mitzva when obligated is even more praiseworthy:
 
Chiddushei Ha-Ritva Kiddushin 31a…For this [person], who is commanded, the Satan [evil inclination] incites, whereas this [person who is not commanded], the Satan does not incite.  The reward is in accordance with the difficulty.  And our great Rabbi of blessed memory [Ramban] explained that mitzvot are not for the benefit of God who commands, but for our merit, and one who is commanded fulfills the King’s decree and therefore his reward is greater than this [person] that did not fulfill the King's command.  In any case, even he is fit to receive reward, for he brought himself into doing the mitzva of God from goodness of heart and piety.…
 
Ritva makes two points:
 
I. We experience more tension when we must act out of obedience than when we freely choose to act.  Surmounting that tension as faithful servants of God merits special reward.
 
II. Mitzva performance is first and foremost an act of obedience to God, a response to God's call. One who is not commanded acts piously, but cannot receive reward for submission to God's decree.
 

●Why doesn't individual initiative count for more? (See Appendix Three.)

Can Custom Obligate?

Can voluntary performance become obligatory?
 
Thirteenth century tosafist Rabbeinu Peretz, writes that in voluntary performance, women "bring themselves into the obligation:"[14]
 
Hagahot Semak 92 (in the name of Rabbeinu Peretz) And in any case, we are accustomed to blow shofar for women who have just given birth, and we also recite a beracha and it is not a beracha in vain, because they bring themselves into the obligation, just as with lulav.
 
What does this mean? Given that the Torah does not obligate women in these mitzvot, perhaps this phrase tells us only that women act as though obligated, and this commitment is noteworthy. But it may indicate that there are other mechanisms that can trigger a different, secondary form of obligation.
 
Binding Communal Custom A community can take a practice upon itself, transforming that practice into custom. A custom can sometimes become so prevalent and entrenched that it takes on a sort of obligatory status. 
 
For example, the Talmud concludes that the evening prayer of aravit (ma'ariv) is reshut (for men).  But, since men have adopted this prayer as a longstanding practice, it becomes like an obligation:[15]
 
Rif Berachot 19a Where they pray tefilat aravit, it is considered upon him as an obligation.
 
Are there any examples of women having a binding communal custom to perform positive time-bound commandments? There is a near universal custom for Jewish women to hear the shofar on Rosh Ha-shana, even though it is a positive time-bound commandment, and for communities to treat that practice like an obligation. 
 
As early as the fourteenth century, Maharil notes the implications of this quasi-obligation for individual women and for the community as a whole:
 
Maharil, Laws of Shofar Indeed women are exempt [from shofar], for it is a positive time-bound commandment. But they bring themselves into the obligation. Since they obligate themselves, they must make haste to prepare their needs, whether in adornment or in cooked dishes, to be available to come to the synagogue and to be there to hear the shofar blast, and they should not impose upon the congregation to wait for them.
 
Here, again, we see the language of "They bring themselves into the obligation." Maharil adds that, when a community of women takes on a mitzva as a group, it is as if its members "obligate themselves."  Since this is not standard obligation, Maharil urges women to fulfill it in a way that respects communal needs. 
 
Centuries later, Magen Avraham and Rabbi Akiva Eiger extend the idea of communal obligation to other mitzvot. Magen Avraham notes that, since women of his day count the omer, it has become like an obligation:[16]
 
Magen Avraham OC 489:1 Women are exempt from counting, for it is a positive time-bound commandment, and nevertheless it is already considered upon them as an obligation.
 
His language is the same as that of the Rif referring to men and the evening prayer. Similarly, Rabbi Akiva Eiger, when discussing women's observance of mitzvot, notes that "women have accepted it upon themselves."
 
Responsa of Rabbi Akiva Eiger 1 It seems that in truth they [women] are not obligated in this mitzva since it is time-bound, but since in any case most of our women are stringent for themselves and are scrupulous and eager to fulfill most positive time-bound commandments, such as shofar, sukka [and] lulav and so too kiddush on Yom Tov, and it is as if they have accepted it upon themselves.
 
Note Rav Eiger's positive terminology to describe voluntary performance. In his experience Women are "stringent," "scrupulous" and "eager" to perform these mitzvot. 
 
In practice, of the Torah-level time-bound mitzvot, only shofar has been taken on in full, and may be considered binding on women on a communal level. In some communities, we might add recitation of Shema and taking lulav.
 
Objection Minchat Chinuch challenges the assertion that communal practice can obligate women in any way. He questions the comparison to the evening prayer, and denies any binding status to the act.
 
Minchat Chinuch 306:1…And this is a new idea that women, if they accept upon themselves to perform a positive mitzva from which they are exempt, they should be obligated because it is considered upon them an obligation. And I have not seen this in any place and it is not similar to the evening prayer…  And here, there are opinions that it is prohibited for them to perform a positive time-bound commandment and all agree that is not a mitzva at all, so how could it be considered an obligation?
 
"All agree that [it] is not a mitzva at all." Minchat Chinuch seems to reject the viewpoint of the sources we have seen that do recognize a mitzva element in voluntary mitzva performance. 
 
Although many halachic authorities disagree with Minchat Chinuch here, his question reminds us of how far we have come: from Torah-level exemption, to arguably permissible voluntarism, to debating binding custom.
 
Personal Obligation Another path to something like obligation is personal. An individual’s commitment to a certain practice can be binding as a form of neder, vow.[17]
 
Mishna Berura 597:6 A practice of doing a mitzva becomes like a vow only if he is accustomed to it, or if [he did it] even one time and had in mind at the time of doing it that he would practice this forever.
 
For example, a woman may regularly take lulav. If she later decides she does not wish to continue the practice, she needs to be formally released from the neder before a bet din, hatarat nedarim. However, according to Rav Ovadya Yosef, no formal release would be necessary if circumstances beyond her control got in the way of her performing it.[18]
 
A woman's personal, consistent commitment may give a dimension of obligation to her voluntary mitzva performance, like a binding custom. However, neither communal binding custom nor self-obligation is equivalent to regular mitzva obligation. A woman who has always been careful to hear shofar is still not obligated in shofar the way men are, from the Torah, and that difference has halachic consequences.
 

● How does this discussion affect a woman performing a mitzva from which she is exempt? (See Appendix Four.)

Advisability

 
We've learned that women receive reward for performing mitzvot voluntarily. Does this mean that a woman should make an effort to perform mitzvot from which she is exempt?  
 
Surprisingly, a statement in the Yerushalmi seems to imply just the opposite:
 
Yerushalmi Berachot 2: 9 And Chizkiya taught: Anyone who is exempt from a matter and does it is called a hedyot (a simpleton). 
 
The Yerushalmi appears to assert that voluntary mitzva performance by one exempted is pointless and to be discouraged. 
 
Ramban[19] explains, however, that this principle is not at all what it at first seems:
 
Ramban Kiddushin 31a Behold, we say in the Yerushalmi, ‘Anyone who performs something in which he is not commanded is called a simpleton!’  That refers to a person who does something that is not commanded from the Torah at all, where it is as if he adds to the Torah. But someone who does the mitzvot of the Torah as enacted even though he was not commanded in them, like women or a non-Jew, receives reward for them, for all of her [the Torah's] paths are paths of pleasantness.
 
When an action is not commanded for anyone, as for example sitting in the sukka on Pesach, performing it has no value.  When someone invents a “mitzva,” he or she diverges from the Torah. That is the case in which one is called a hedyot.
 
This label does not apply when a person voluntarily performs a genuine mitzva from which she, personally, is exempt, especially if we view performance as reshut de-mitzva. Voluntary action in this case is a reflection of yearning for mitzvot, not the act of a simpleton.[20]
 
If we view voluntary mitzva performance as a reshut de-mitzva, then we should generally encourage it, when it does not conflict with other religious obligations or values.[21] Rav Yisrael Ze'ev Gustman (Lithuania and Israel, 20th century) makes this case forcefully:
 
Rav Yisrael Gustman, Kuntresei Shiurim, Kiddushin, p.254 In my humble opinion, it seems warranted to rule that even in positive time-bound commandments, it is not worthy for women to free themselves from these mitzvot if not for some [other] mitzva [whose time is] passing or because of excessive effort… The mitzva act is from the Torah, and from the Torah it is [considered] reshut de-mitzva.
 
Let's leave the last word to Rabbanit Chana Henkin, who values both fulfilling command and voluntarism. Rabbanit Henkin sees beauty in how a woman’s relationship with mitzvot lies at various times within each of these categories.[22]
 
Chana Henkin, Einah Metzuvah v'Osah in a post-Modern World Einah Metzuvah v'Osah [she is not commanded and does] gives us freedom, spontaneity, and meaning. Metzuveh v'Oseh [commanded and does] ensures that we are worshipping God, not ourselves. By the nature of their role in Judaism, women partake of both.
 

APPENDIX ONE: Why should anyone question voluntary performance? 

 
Mitzva literally means commandment.  What does it mean to perform a command in which one is not commanded? To do God's bidding unbidden? 
 
The Ran raises the concern that when we perform a mitzva without being commanded, we risk missing the essential point of the mitzva. 
 
Derashot Ha-Ran 7
 
One who is not commanded and performs, his reward will not be great, for it is possible that God does not desire [performance of that mitzva by] him and his sort, since He did not command him… Mitzvot may have reasons whereby the mitzva is specifically intended for the one who is commanded and performs… for it is possible that the intention and inner nature of the mitzva will not be fulfilled through one who is not commanded and performs as it is fulfilled by one whom God commanded.
 
Ran points out that God determines the meaning of each mitzva, who is obligated in it, and who is exempt. A mitzva’s deeper significance may be linked to the class of people who are commanded in it. If God exempted me, that very exemption may indicate that my voluntary performance would not have the same religious meaning as a commanded performance.
 
The significance of voluntary performance of a mitzva might be fundamentally different from the meaning of the mitzva when performed by one who is obligated.
 
APPENDIX TWO: Can't benei refer to sons and daughters?
 
Hebrew grammar refers to a mixed-gender group as a masculine plural, so that the word "benei" can mean 'sons of' or ‘children of.' Sometimes the Torah refers to all Jews as a group and sometimes it explicitly distinguishes women from men. In ambiguous cases, such as the word "benei" in this verse, our sages often stipulate which meaning is correct. Whether or not females are included varies from verse to verse, and thus depends on both context and tradition.[23]
 
Midrashic readings often provide textual derivations for a halacha. Those derivations, following carefully formulated traditional exegetical rules, can be the actual source of the halacha. Sometimes, however, a midrash expounds texts in order to uphold previously known halachic traditions and connect the tradition to the text.
 
This particular midrash halacha is likely a midrash of the second type, upholding a previously known tradition that men lean physically on their individual sacrifices while women don't. In other words, the answer to 'why is there an exemption?' does not necessarily boil down to the interpretation of "benei" as "sons of." Rather, the explication of the verse aligns with an accepted tradition as to who was obligated to lean on their sacrifice and who was not. 
 
In this case, both positions in the dispute agree that "benei" means males. They only disagree about the halachic implications of that reading.
 

APPENDIX THREE: Why doesn't individual initiative count for more?

Halacha's preference for commanded performance over voluntarism can be difficult to accept.  Post-enlightenment, we tend to emphasize autonomous initiative over obedience to authority. 
 
But from the perspective of authority, while both autonomous initiative and obedience can be valuable, obedience is more crucial. Initiative waxes and wanes, and may be misdirected. Obedience is steady and loyal. 
 
The desire to elevate autonomy at the expense of obedience can lead to worship that is more about the self than about relationship to the Divine "Other."
 
A person overly concerned with autonomy might say, "I was about to do it, but now that you told me to, I won't." A more mature person takes pleasure in answering a beloved's request, with no need to mention that he or she was about to do it anyway.  This type of person values acting in faithful response to the Other's call.
 

APPENDIX FOUR: How does this discussion affect a woman performing a mitzva from which she is exempt?

 
Let's use lulav as an example. A women is not obligated to take lulav, but is permitted to take it if she wishes. When resources are scarce, for example, there aren't enough lulavim to go around, the difference between men’s and women’s obligations can affect practice. We should enable those who are fully obligated to perform their obligations before those who have chosen to do so voluntarily. 
 
But often nowadays we are blessed with plentiful resources. What then?
 
When there is no binding communal custom, a woman can choose to avail herself of flexibility. Halacha allows for that. If a woman doesn’t take lulav, there are no negative consequences.  
 
If, on the other hand, she chooses to take lulav, it not only gives her gratification (which Halacha recognizes as important), but also counts as a fulfillment of a mitzva, and if she is accustomed to performing a given mitzva voluntarily, she cannot forgo it lightly.
 
Granted, women choosing to take lulav do not receive the reward of responding to an obligation. But women's taking lulav is not just play-acting. It is a mitzva act in service of God, recognized by God.
 
Even in the absence of direct obligation, a woman's experience of performing a mitzva voluntarily is not lacking. Rather, it is a rich, authentic, and meaningful Avodat Hashem.
 

[1] This is not to be confused with the use of the term to refer to rabbinic ordination, a different form of laying on of hands. 
[2] Sifra Chapter 2 Section 2:2 The sons of Israel lean and the daughters of Israel do not lean.
[3] In theory, one could argue that semicha is time-bound because the Temple service is not performed at night.
[4] Rosh Ha-shana 33a We do not prevent children from blowing [shofar]. This [implies that] we do prevent women. Isn’t it taught: We do not prevent either women or children from blowing [shofar] on the festival! Abaye said, It is not difficult. This is according to Rabbi Yehuda and this is according to Rabbi Yose and Rabbi Shimon. As it is taught: "Speak to benei Yisrael" – The sons of Israel lean and the daughters of Israel do not lean; these are the words of Rabbi Yehuda. Rabbi Yose and Rabbi Shimon say: Women lean [as a matter of] reshut (permission)
[5] Devarim 13:1 All that which I command you, be careful to perform, do not add to it and do not subtract from it.
[6] This discussion refers to a woman blowing shofar on Rosh Ha-shana, or to a man blowing shofar specifically for women. All authorities agree that a woman may listen to a man blowing shofar for the community.
[7] This reading is consistent with another Talmudic passage, where Rabbi Yehuda cites a woman’s sukka as support for his position that a sukka may be as high as 45 cubits.
Sukka 2b Rabbi Yehuda said: It happened with Queen Heleni in Lod that her sukka was higher than twenty cubits and the sages would come in and out of there and did not say anything to her [about the sukka being too high]. They said to him, [You bring] a proof from there? She was a woman and exempt from the [mitzva of] sukka. He said to them, Did she not have seven sons? And further, all her deeds she did only in accordance with the sages.
In this passage, Rabbi Yehuda gives no indication that he disapproves of Queen Heleni’s voluntary mitzva performance.  There is no ancillary reason to stop a woman from sitting in a sukka, so Rabbi Yehuda permits it. 
[8] Paralleled almost verbatim in Chagiga 16b.
[9] See, for example, Sefer Yere'im, who does not allow men to blow shofar for women, because the violation of muktzeh cannot be justified for men when women hear shofar merely for gratification:
Sefer Yere'im 419 For themselves we permit for gratification but for another, no. For we do not say to a man [to] sin [just] because of women's gratification.
[10]  Another way to refer to this is as a mitzva kiyyumit, from the language of kiyyum, fulfillment, as opposed to a mitzva chiyyuvit, a mitzva with a chiyyuv, obligation.
[11] See also Ritva:
Chiddushei Ha-Ritva Rosh Ha-shana 29b For even though they [women] are not obligated, there is a mitzva upon them and they receive reward for them.
[12] It is not clear if such performance is considered a fulfillment of the original mitzva or is a separate fulfillment of 'eina metzuva ve'osa'. Rabbeinu Tam's view may well be the latter. See Shu"t Shevet Ha-levi 8:1.
[13] The Ra'avad also writes a version of this strong formulation in his commentary to the Sifra.
Ra'avad to Sifra Dibura Dinedava 2:2:2 It is permitted for women for so was it given in the Torah to men as an obligation and to women as optional, and women are like men for [fulfillment of] all positive time-bound commandments…
Here, however, he is explaining the viewpoint of Rabbi Yosei and Rabbi Shimon, not presenting his own halachic ruling.  Cf. his gloss to Rambam, Laws of Tzitzit, where he does not permit women to wear tzitzit of kilayim. If it were a Torah-level mitzva on par with a man's, that should be permissible as it is for men.
Mishneh Torah, Laws of Tzitzit 3:9 Gloss of Ra'avad Specifically, [a woman may don] tzitzit that does not have shatnez.
[14] Compare to the words of Rashi's teacher Rav Yitzchak Ha-Levy, in the eleventh century:
Machzor Vitry 359 Rav Yitzchak Ha-levi ruled that…They [women] are not obligated and do not need to [perform them], but if they desire to bring themselves into the yoke of the mitzva, the permission is in her hand and we do not rebuke her… 
[15] See Mishneh Torah, Laws of Prayer, 1:8, “All Israel in all the places that they dwell have the practice to pray aravit and accepted it upon themselves as an obligatory prayer.”
[16] Nowadays, it seems to have fallen back out of the realm of communal obligation, since it is less widely practiced.
[17] Shulchan Aruch YD, Laws of Vows, 214:1-2 Things that are permitted, and people who know that they are permitted treat them as forbidden, it is as if they accepted upon themselves a vow and a prohibition to permit them to themselves; therefore, one who is accustomed to fast the fasts before Rosh Ha-shana and between Rosh Ha-shana and Yom Kippur, and one who is accustomed not to eat meat or drink wine from the first of Av or from the 17th of Tammuz and wishes to reverse himself because he is not healthy, requires [a bet din of] three to permit him.
If at the time that he began a practice, he intended to continue it forever, and acted thus even one time, he requires annulment and should open with regret, that he regrets acting thus as a vow. Therefore, one who wishes to practice [abstention from] a few permissible things, as a caution and abstinence, should say at the outset that he does not accept this practice upon himself as a vow, and he should also say that he does not intend to act this way except that specific time, or at times that he chooses, and not forever.
[18] Responsa Yabi'a Omer II O.C.:30 If she wants to annul her custom absolutely, she needs [formal] release [from her vow], but if circumstances beyond her control happened at one time, and her intention is not to annul her custom forever, she does not need a [formal] release.
Ben Ish Chai, disagrees in the case of shofar, and does require hatarat nedarim. It's not clear if he would also disagree in other cases in which the mechanism of obligation is personal, not communal.
Ben Ish Chai Shana Rishona Nitzavim 17 Women are exempt according to the law because this is a positive time-bound commandment, but most women have set this mitzva upon them as an obligation, and come to synagogue to hear the sound of the shofar. Therefore, if becomes an obligation upon a woman who has acted this way for years, and if circumstances beyond her control make her unable to come to synagogue…and also she is not able to bring a shofar-blower to her home, she should make a [formal] release [of vows] on the eve of Rosh Ha-shana on accepting the custom.
[19] See also Ritva and Meiri ad loc.
[20] Rav Moshe Feinstein adds the caveat that voluntary mitzva performance is only acceptable when a woman's soul yearns to perform a Torah mitzva from which she is exempt, not if she seeks to undermine the exemption.
Igrot Moshe OC 4:49…It is clear that it is only [permitted] when her soul desires to fulfill a mitzva even when she was not commanded.
[21] We will see, for example, that there are constraints on a woman laying tefillin or wearing a tallit. An example of this perspective on reshut can be found in Tosafot:
Berachot 27b Tosafot s.v. Halacha It is called reshut to annul [its performance specifically] for the sake of another mitzva [whose time is] passing.
Notably, Rav Ovadya Yosef discourages voluntary performance, because it may distract from other obligations.
Yabi'a Omer I O.C. 42 This is the counsel of the evil inclination, for before they go to fulfill mitzvot that they are not obligated in, they should fulfill that which is imposed on them.
[22] Available here: https://www.nishmat.net/Uploads/files/Rabbanit_Henkin_Womens_Issues1.pdf
[23] An example of women being included is receiving blessing:
Bava Batra 110b “So that your days and children's days will be many,” is this also your sons and not your daughters? [No, women are included, for] a blessing is different.