Tefillin are the religious items a Jewish boy is traditionally expected to begin wearing regularly after becoming bar mitzvah.
Tefillin are small black leather boxes containing handwritten parchment passages from the Torah. One box is tied to the arm and another to the head during weekday morning prayers. The practice follows biblical verses that command binding these words as a sign on the hand and between the eyes.
In many traditional communities, boys learn to put on tefillin before their bar mitzvah so they can perform the practice correctly once they reach religious obligation. The exact timing of instruction and the customs governing use differ among Jewish communities. Tefillin are generally not worn on Shabbat or major Jewish festivals.
Tefillin are not the same as a kippah or tallit. A kippah is a head covering, while a tallit is a prayer shawl. Tefillin have a specific ritual function and contain sacred texts, making them a distinctive part of weekday Jewish prayer.