by R. Daniel Mann
Question: May one try on tefillin at night, or does that fall under the category of not putting on tefillin at night?
Answer: I have not found this exact question in the poskim, so we will extrapolate based on the principles and similar cases,
The gemara (Menachot 36b and several other places) cites a machloket between Tannaim whether the night and/or Shabbat and Yom Tov are times during which one wears tefillin. Much depends on the pasuk (Shemot 13:10), ending off the section of “Kadesh li,” referring to mitzvot commemorating yetziat Mitrayim, including tefillin: “You shall guard this statute at its time from days to days.” Some understand it to indicate that there are times of the day (daylight) and certain days (not Shabbat) in which tefillin is worn, and others not. Some Amoraim (ibid.) say that one who dons tefillin at night violates a Torah prohibition, either a positive one and or even a negative one. The Rambam (Tefillin 4:10) accepts the latter opinion.
However, most Rishonim (see Beit Yosef, Orach Chayim 30) and the Shulchan Aruch (OC 30:2) follow what the gemara apparently learns from a story about Rav Ashi, that he posited that fundamentally one can fulfill the mitzva of tefillin at night. The gemara does conclude that we do not teach people to do this. Rashi (Menachot 36b) and many others explain that there is a concern that if one wears tefillin at night, he might fall asleep with them on, which is forbidden lest one pass gas (Sukka 26a).
The gemara (Eiruvin 95a, Menachot 36b, Beitza 15a) discusses the possibility of wearing tefillin under non-standard circumstances and intentions at night and/or on Shabbat/Yom Tov. The main case is when it is required to bring the tefillin to a safe place. It seems to be permitted whether or not these times are fundamentally slated for tefillin to be donned (Eruvin 95b). Even the Rambam (ibid. 12) can allow a potential Torah violation either because he does not intend to wear them for the purpose of a mitzva or because he is only keeping them on rather than putting them on (see Shaagat Aryeh 43).
The leniencies of not intending to fulfill the mitzva and only keeping them on actually do not seem to apply according to the approach that the reason we don’t wear tefillin at night is only Rabbinic. After all, that does not reduce the chances of falling asleep. Therefore, the logic behind permission to wear tefillin to protect them is connected to the need to protect holy articles from loss or disgrace, which is often a halachic factor (see Shabbat 115a). The gemara (Menachot 36a) does also allow one who is leaving his house too early for tefillin to put them on and make the beracha when the right time comes. Another important factor seems to play a role – this is his only viable way of fulfilling the mitzva (see Mishna Berura 30:10).
However, many (including Shulchan Aruch, OC 30:3) identify another factor, which we should consider in our case. We are referring to one who has woken up for the day (albeit, early), and therefore, we do not need to be concerned that he will fall back asleep. Similarly, one might argue that one who is just trying on tefillin should not be concerned he will forget about them until he falls asleep, at least if it is not late at night. However, this apparently is not sufficient to allow putting on tefillin for this reason. Chazal and classical poskim set the parameters for when one has to be concerned about sleep. The Shulchan Aruch (ibid. 5), for example, says that if one has already davened Maariv before nightfall, it is forbidden to put on tefillin because it is halachically night. The Mishneh Sachir (I:13) remarks that the halachic categorization of night is the factor, not the likelihood of sleep. Therefore, it is difficult to argue that the fact one plans to take off the tefillin quickly makes a difference. However, it is conceivable that one would give a lenient ruling if it is crucial for him to do so specifically at night (e.g., it is the only time someone is available to adjust the tefillin for a bar mitzva boy).