Ask the Rov: Why do we choose not to wear “undershirt tzitzis” or regular tzitzis directly on the skin?
By Rabbi Chaim Hillel Raskin – Rov of Anash in Petach Tikvah
For a tallis katan to be kosher, it must be a (a) four-cornered (b) cloth (c) garment. These are relevant for fulfilling the mitzva, reciting the bracha, and possibly “carrying” the strings on Shabbos (if the garment doesn’t need tzitzis).
Four-cornered: To be “four-cornered,” it must be open on both sides along the majority of what hangs below the arms. Buttons or tight hooks cannot close the lower half of the garment’s length.1 To perform the mitzva according to all opinions, the Alter Rebbe recommends that the garment be completely open on both sides, without any clips or seams, including openings for the arms.2
In addition, the shoulder areas together must be wider than the neck cutout. If not, the shoulder areas are considered insignificant (bottel) and invalid.
Cloth: To be considered “cloth,” a tallis katan should be of wool, ideally (see issue 475), or some other natural fiber. A garment made of netted or synthetic material is of questionable obligation.3
Garment: There is debate whether a garment meant to absorb sweat is halachically considered a proper garment (e.g., for kriah R”L) and is therefore exempt from tzitzis.4 With garments designed to be tzitzis and also be worn on the skin, some poskim posit that one’s intention for the mitzva makes it into a “garment,” while others argue that in fact it absorbs the sweat. If it is meant to serve as an undershirt, it is especially problematic, even if it is worn as the only layer of clothing (i.e., a t-shirt).5
A further issue with wearing it on the skin, which is relevant even for a regular tallis katan, is disrespect to the mitzva by wearing it directly on the body. Some counter that tefillin are wrapped directly on the body and it’s not an issue.6 Yet, there is reason according to Kabbalah to have a separation between the tallis katan and one’s body.7 One may be lenient for children to wear regular tzitzis on their bodies.
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From The Weekly Farbrengen by Merkaz Anash