What are tefillin?

Tefillin, also called phylacteries, are small, black leather cubes containing passages from the Torah - which includes the first five books of the Old Testament - attached to the arm and head with leather cords.

They are traditionally worn by observant Jewish men and boys of 13 or older, for prayer on weekday mornings.

Made from the skin of kosher animals, they serve as a reminder of God's presence, one rabbi explained.

Among the passages, written in kosher ink on parchment, are references to the escape of the Jews from slavery in Egypt, the nature of God, and the command for the righteous to pray using the tefillin.

One of the black boxes, called the shel yad, or hand tefillin, is placed on the biceps of the left arm, resting against the heart. It is suspended on a black-painted leather strap which is wrapped seven times down the left arm and then in a circumscribed pattern around the left hand.

The other tefillin, the shel rosh, or head-tefillin, is placed on the head, the center of thought, and held in place with straps knotted in the back of the head.

Two straps of the head-tefillin are placed in front of the shoulders.

- Various sources