TEFILLIN should in principle be worn all day, but since a person must keep his mind on them at all times, and must keep his body clean while wearing them, it is customary to wear them only during the morning prayers (see 37:2;25:3-4,13). They should be put on after putting on a garment that has TZITZIS (a TALLIS; see 25:1-2). If possible (see 26:1-2), the arm phylactery should be put on first (25:5-6,11). The blessing “…Who commanded us to put on TEFILLIN” is recited before the arm phylactery is fastened, and the blessing “…Who commanded us about TEFILLIN” before the head phylactery is tightened; see 25:5,7-10. On situations in which the blessings must be repeated see 25:12.
The arm phylactery is placed on the lower part of the upper left arm, with the box slanted toward the body, near the heart (27:1,6-7). The passage for the strap faces upward, and the “yud”-shaped knot is at the end of the passage, pointing inward (27:2-3,10). It is customary to pass the strap through a small loop at one end of the passage and wind it seven times around the arm and three times around the middle finger (27:8). The head phylactery is placed above the hairline, centered above the nose. The two ends of the strap are tied in a “dalet”-shaped knot to form a loop that goes around the head, with the knot centered at the back of the neck (27:9-10); the ends of the strap beyond this knot hang down in front of the body, at least to the navel (27:11). The bases of the TEFILLIN should be in direct contact with the body (see 27:4-5), and the head phylactery should not be covered (see 27:11). The black sides of the straps should face outward (27:11).
TEFILLIN should be put on while standing; see 25:11. While wearing them, a person should touch them frequently — first the arm phylactery, then the head phylactery (28:1). It is customary to kiss them while putting them on and removing them (28:3). They are removed while standing — first the head phylactery, then the arm phylactery (28:2). No blessing is recited when they are removed (29:1).
TEFILLIN may be put on in the morning after it is light enough to recognize an acquaintance (30:1). If it is necessary for a person to put them on earlier, when it becomes light he should touch them and recite the blessings (30:3). A person must not put them on at night or after the evening prayers (30:2,5) because he might sleep in them, and he should remove them after sunset unless there is no safe place to put them (30:2,4). They must not be worn on the Sabbath or on holidays (31:1). Opinions differ about wearing them on the intermediate days of the holidays (31:2); in any case, on those days and on the New Moon they are removed before the additional service (MUSAF; 25:13;31:2). They are worn on the Ninth of Av (38:6).
Women and children should not wear TEFILLIN (37:3;38:3). A person who cannot think proper thoughts while wearing them, or who cannot keep his mind on them, or who is likely to become drunk, or who has a digestive sickness, should not wear them (38:1-2,4,7,9). A mourner does not wear them on the first day (38:5), and a leper and a person who is under a ban must not wear them (38:13). Those who are occupied with other Commandments are excused from wearing them unless they are able to do both; see 38:8,10. On wearing TEFILLIN in the presence of one’s teacher see 27:11;38:11.
TEFILLIN must handled with respect (40:1). On keeping them in one’s bed or having marital relations in their presence, or sleeping while wearing or holding them, see 40:1-7;44:1. On wearing them while eating see 40:8; on taking them into a toilet or bathhouse or a place where there is excrement see 43:1-9;45:2. On carrying a load on the head or going near a grave or dead body while wearing the head phylactery see 41:1;45:1. Things that were intended for use in TEFILLIN, or that were used for TEFILLIN with the intent of using them only for that purpose, must not be used for secular purposes (42:3).
Shulchan Aruch, Copyright (c) 2000 Project Genesis, Inc.