Wearing Tefillin All Day Long

Why do I see some people wearing Tefillin all day long?

Shalom!

Thank you for your question!

As I am sure you’re aware, tefillin are generally only worn during the weekday morning prayers. That being said, however, tefillin is indeed a mitzva that is in effect all day long. It was very common for tefillin to be worn in ancient times all day long, just like the tallit-katan garment is worn all day long even today. Although wearing tefillin all day long might be very meritorious, as we will see, it is quite rare nowadays.

One of the reasons that tefillin ceased to be worn all day long was due to the anti-Semitic environment that the Jews lived in throughout the centuries of the Diaspora. In fact, in some places, this led to tefillin being neglected completely. As the Rashba writes, “Very few Jews put on tefillin [these days].” This went on for several generations.

Thankfully, all observant Jews wear tefillin nowadays and wearing them only for the morning prayers is perfectly acceptable. This is because wearing tefillin requires one to have a “ guf naki” (a clean body) which is very difficult to maintain. A guf naki is defined as not needing to pass gas, not having any bowel disorders, and being sure to keep a clean and pure mind. So too, there is a requirement that one be constantly aware that one is wearing tefillin while one wears them. These requirements are difficult to maintain all day long and therefore the rabbis decided not to require wearing tefillin all day long even if it might be the ideal. Wearing tefillin during the morning service is most important so that one would recite the Shema and Shemoneh Esrei while wearing them.

As you correctly note, there are indeed those who wear tefillin all day long and while this is commendable for those who can maintain a guf naki, it is not realistic for most of us.

Megilla 28; Taanit 20b; Shabbat 118b, 130a; Tosfot, Shabbat 49a; Rambam, Hilchot Tefillin 4:25; OC 28:1,4, 37:1,2, 38:1,4; Levush , OC 37:2;