Q. I have seen some people remove their Tefilin on Rosh Chodesh before the reading of the Torah. Is there a source for that minhag?
A. Levush (423: 4) offers another reason for removing the Tefilin on Rosh Chodesh, before Musaf, as mentioned because tefilin is referred to in Chumash Shemos (13 : 9.88) as an “os” (sign) and Yom Tov is also referred to as an “os.” It is inappropriate to wear tefillin on Yom Tov since this detracts from the “os” of Yom Tov. Although Rosh Chodesh does not have the same sanctity as Yom Tov, and is not referred to as an “os,” the korbanos of Rosh Chodesh are listed together with the other holidays. Therefore, before Musaf, in which we will mention the korbanos brought on Rosh Chodesh, it is appropriate to remove one’s tefillin. The Levush therefore writes that one should remove tefillin before krias haTorah, since the kriyas haTorah for Rosh Chodesh is also about the korbanos of the day. The Magen Avrohom (423:6), however, rejects the opinion that tefillin should be removed before krias haTorah. He writes that since removing tefillin is a chumra, we do not remove tefillin for krias haTorah, but only for Musaf.
Indeed, if someone attends a shul where the take off tefillin before krias haTorah, he should then follow their custom.
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu and Horav Kalman Ochs Shlit’a.