The Bible tells us: And you shall bind them as a sign on your arm, and they shall be as frontlets on your head between your eyes” (Deuteronomy 6:8.) Though of course the details are much more complex than this…. The Torah tells us in four places that we should bind the Tefillin.
The four place this is mentioned is
Deut.6:4-9 Deut. 11:13-21 Exodus 13:1-10 and Exodus 13:11-16
Each of these places is a separate chapter in the Torah
Basic Tefillin laws:
Consult a reliable Rabbi
1. If for some reason you have only one half of the set, whether it be only the one for the head, or only the one for the arm, put that one on and recite only the blessing for that one. 2 . When putting on tefillin it is very important to have a clean body. In addition to general cleanliness, one must be especially careful to be clean after going to the bathroom.
3 . Someone who has no control over what comes out of his body is forbidden to wear tefillin. Anyone in that situation should discuss it with his Rabbi to find out when and how he may
wear tefillin. 4. One should go to the bathroom before putting on the tefillin, or at least be absolutely sure he will not have to go while wearing the tefillin. If while wearing tefillin you feel the need to go, you must remove the tefillin and go. 5. If you feel the need to pass gas while wearing tefillin, you must first remove your tefillin. 6 . Never take tefillin or any holy item into a bathroom. While wearing tefillin, one should only think about clean things.. As well as speaking out loud. 7. We may not wear tefillin at night. 8 . We do not put on tefillin on the Sabbath. 9 . While putting on Tefillin, one may not talk from the first blessing through the Statement. [Until Step C, see below]
10 . One who is a righty
binds the Tefillin on his left arm; one who is a lefty binds the Tefillin on his right arm. (Same style just opposite sides.) 11. Tefillin should be put on your weaker hand. If you are right-handed, use your right hand to put your tefillin on your left hand. If you are left-handed, use your left hand to put tefillin on your right hand. If you are ambidextrous, ask your Rabbi, because each case is different. If you are unable to contact a Rabbi for some reason, assume in the interim that the hand with which you write is your stronger hand (for this purpose, at least). Always treat your tefillin with the greatest of respect and reverence. Do not remove them from the bag by shaking them out of the bag, for example. Always take them out carefully, and put them back carefully. To show our love for one of the greatest deeds, we use our stronger hand to put the tefillin onto our weaker hand. We also use our stronger hand to put the tefillin on our head. When taking off the tefillin, we use our weaker hand, to show our reluctance to take off the Mitzvah.
Tefillin are made of leather. That means that you must keep them safe from things that hurt leather, like moisture and extreme temperatures.