409. Paying Attention to the Tefillin

Tefillin, Mezuzah v’Sefer Torah 4:14

A person should touch his tefillin periodically while wearing them so that his attention will not be distracted from them even for a moment. The sanctity of tefillin surpasses even that of the tzitz (the Kohein Gadol’s headplate). The tzitz has God's Name written on it once, but the head tefillin – and, also, the arm tefillin – contains the Tetragrammaton 21 times.

Tefillin, Mezuzah v’Sefer Torah 4:15

Tefillin require a person to be physically clean, meaning that one should strive not to break wind while wearing them. Therefore, one is not permitted to sleep while wearing tefillin – not even a nap. If one covered his tefillin with a cloth and he doesn’t have a woman with him, then he may nap in a seated position while wearing them.