Halakhah for Eruvin 191:14
ודילמא סבר לה
Now, since according to the view of the first Tanna the night is a proper time for the wearing of tefillin,<span class="x" onmousemove="('comment',' From which it is obvious that he does not apply Ex. XIII, 10 (which excludes the nights as well as Sabbaths and festivals) to the commandment of tefillin but to that of the Passover.');"><sup>43</sup></span> Sabbath also must be a proper time for the wearing of tefillin. But is it not possible that he holds that the night is a proper time for tefillin<span class="x" onmousemove="('comment',' Since he applies Ex. XIII, 10, to the Passover and not to tefillin.');"><sup>44</sup></span> but that the Sabbath nevertheless is not a time for it, since we have in fact heard R'Akiba to state that the night is a time for the tefillin and that the Sabbath is not?<span class="x" onmousemove="('comment',' As was deduced supra from Ex. XIII, 9.');"><sup>45</sup></span> - It<span class="x" onmousemove="('comment',' The first ruling in our MISHNAH:');"><sup>40</sup></span> represents rather the opinion of the following Tanna. For it was taught: Michal the daughter of the Kushite<span class="x" onmousemove="('comment',' Sc. Saul who was so described (cf. M.K. 16b) .');"><sup>46</sup></span> wore tefillin and the Sages did not attempt to prevent her, and the wife of Jonah<span class="x" onmousemove="('comment',' The son of Amittai, the prophet.');"><sup>47</sup></span> attended<span class="x" onmousemove="('comment',' Lit., 'was going up to'.');"><sup>48</sup></span> the festival pilgrimage and the Sages did not prevent her. Now since the Sages did not prevent her it is clearly evident that they hold the view that it<span class="x" onmousemove="('comment',' Tefillin.');"><sup>49</sup></span> is a positive precept the performance of which is not limited to a particular time.<span class="x" onmousemove="('comment',' But may be performed at all times including the nights. Sabbaths and festivals. Had its performance been limited to particular times women would have been exempt from the duty of keeping it and Michal who would be guilty of adding to the commandments would have been required by the Sages to abandon her practice.');"><sup>50</sup></span> But is it not possible that he<span class="x" onmousemove="('comment',' The author of this Baraitha.');"><sup>51</sup></span> holds the same view
Peninei Halakhah, Women's Prayer
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.