Tefillin are a set of small cubic leather boxes painted black, containing scrolls of parchment inscribed with four verses from the Torah, with leather straps dyed black on one side, and worn by observant Jews during weekday morning prayers. There are two boxes of Tefillin, a shel yad, the hand tefillian, which is placed on your arm and wrapped until your palm. The other box is shel rosh, is placed above the forehead, with the strap going around the head and over the shoulders. The Torah commands that they should be worn to serve as a "sign" and "remembrance" that G-d brought the children of Israel out of Egypt. It used to be that people wore Tefillian every weekday. There are some rabbis in Israel who continue that custom, but most Jews just wear it during weekday morning prayers.
The obligation of tefillin is mentioned four times in the Torah: twice when recalling the the Exodus from Egypt:
- And it shall be for a sign for you upon your hand, and for a memorial between your eyes, that the law of the Lord may be in your mouth; for with a strong hand did the Lord bring you out of Egypt.—Exodus 13:9
- And it shall be for a sign upon your hand, and as totafot between your eyes; for with a mighty hand did the Lord bring us forth out of Egypt.—Exodus 13:16
and twice in the shema passages:
- And you shall bind them as a sign upon your arm, and they shall be as totafot between your eyes.—Deuteronomy 6:8
- You shall put these words of mine on your heart and on your soul; and you shall tie them for a sign upon your arm, and they shall be as totafot between your eyes.—Deuteronomy 11:18
All four of these paragraphs are written in the shel rosh. Tefillin is never worn on Shabbos, Yontif, and some people say it is not worn on Chol Hamoed. Women do not wear Tefillin.