408. Who Is Exempt from Tefillin?

Tefillin, Mezuzah v’Sefer Torah 4:12

If a person is wearing tefillin in the middle of a journey and the sun sets, ushering in Shabbos, he should cover the tefillin with his hand until he reaches his destination and then remove them. If he is sitting in the study hall (with tefillin on) and the sun sets, ushering in Shabbos, he should cover the tefillin with his hand until he reaches his home, then remove them. If there is a house near the city wall where his tefillin would be safe, he should leave them there. If he didn’t remove his tefillin after sunset because he didn’t have a safe place to leave them, he may keep wearing them in order to protect them.

Tefillin, Mezuzah v’Sefer Torah 4:13

Anyone who is exempt from to reciting Shema is also exempt from wearing tefillin. If a minor understands about taking proper care of tefillin, his father should get him a pair in order to educate him in the mitzvah. If a person has stomach problems and can only contain his bodily functions with difficulty, he is exempt from wearing tefillin. Those who are ritually impure are still obligated to wear tefillin. If a person is in discomfort, or if he is agitated and cannot concentrate, he is exempt from wearing tefillin. This is because a person wearing tefillin is not allowed to let his attention stray from them. Kohanim performing the Temple service, Leviim singing in the Temple, and Yisraelim attending services in the Temple are all exempt from reciting Shemoneh Esrei and wearing tefillin.