407. Times to Wear (and Not Wear) Tefillin

Tefillin, Mezuzah v’Sefer Torah 4:10

The time for wearing tefillin is day, not night, as per Exodus 13:10, “you shall observe this law in its appointed time, from day to day,” referring to tefillin. Similarly, tefillin are not worn on Shabbos or yom tov as per Exodus 13:9, “they shall be a sign for you.” Shabbos and yom tov are themselves signs, making the additional sign of tefillin unnecessary. The time to put on tefillin starts when one can recognize an acquaintance standing four cubits away (about six feet); it lasts until sunset.

Tefillin, Mezuzah v’Sefer Torah 4:11

It is permitted for one who put tefillin on before sunset to keep wearing them after nightfall, even for the entire night. This law, however, is not taught publicly. Rather, people should be taught not to wear tefillin at night and to remove them before sunset. If a person puts on tefillin after sunset, he violates the Biblical decree of “you shall observe this law in its appointed time, from day to day” (Exodus 13:10).