Tefillin are passages from the Torah that are written on parchment and are placed within leatherbatim (casements), with leather straps attached to the batim. These straps are used to bind the batim and the parchment Torah passages within them on one`s arm and hand and on one`s head.More Details
In our time, the practice is to wear Tefillin during the entire weekday Shacharit service. Since the commandment of Tefillin has its source in the verse "Bind them as a sign on your hand and let them serve as a symbol on your forehead" (Deuteronomy 6:8), on Sabbaths and holidays Tefillin are not put on. The reason for this is that the word "sign" (ot) is also mentioned in the commandment of the Sabbath, as it is written: "The Children of Israel shall keep the Sabbath, observing the Sabbath throughout the ages as a covenant for all time: it shall be a sign for all time between Me and the people of Israel" (Exodus 31:16-17), and one sign (that of the Tefillin) is not placed on another (that of the Sabbath); the Festivals are comparable to the Sabbath.More Details
The Tefillin symbolize the eternal bond between the people of Israel and G-d, and attest that the person attired in them is a Jew connected to his heritage, as is stated in the passage of "Consecrate to Me every first-born," one of theMore Details
he quality of the batim of Tefillin is dependent in great measure upon the amount of time allotted for their drying, especially in the later stages of the production of the batim. The slower and more thorough the drying during the creation of the perfect square shape by grinding, the better the production process and the higher the quality of the Tefillin.More Details
In order to guard the Tefillin against damage that is liable to render them unfit, they must be carefully protected from moisture and heat.