A Mezuzah is a beautiful and special Jewish ritual object used to mark the doorposts of Jewish homes. The word “mezuzah” literally means “doorpost,” and it’s a Jewish door ornament and piece of Judaica that fulfills the commandment for Jews to hang the words of the Bible on their doorposts.Originating in the Torah, mezuzahs consist of two parts - the mezuzah case and the mezuzah parchment scroll called a klaf. The klaf contained inside the case is inscribed with specific Hebrew verses: sections of the Shema prayer beginning with the famous words, Shema Yisrael.
Mezuzahs have two purposes: They serve to remind those entering and leaving of the covenant between Hashem and the Jewish people, and they identify one's dwelling as a Jewish household.
What is a mezuzah made of?
While there are many strict and complex laws surrounding the preparation of the mezuzah scroll, the cases that protect them don't require any particular specifications. Mezuzah cases are often decorative and can be made of a variety of different materials ranging from affordable and lightweight plastic cases to ornate masterpieces made from sterling silver, stone, wood, steel, and more.Mezuzah scrolls, meanwhile, are made from specially-prepared parchment and written by highly trained scribes called sofers, who carefully write each individual sacred letter to perfection. Once the klaf or scroll is complete, it's rolled up and placed inside the mezuzah case. The case is not sealed permanently, as it is recommended that scrolls be checked for damage or defects at least once or twice every seven years. The mezuzah case is affixed to the top third of a doorway on the right, right side up - straight and vertical in Sephardi tradition, and with the top of the mezuzah tilting towards the inside of the room in Ashkenazi tradition. It is customary to keep mezuzahs affixed to every doorway except for bathrooms and small closets.
Mezuzah components
A mezuzah consists of an outer mezuzah case - often beautifully decorated, in a range of possible materials and designs - with a klaf or parchment scroll inside. The mezuzah scroll text, written by a sofer or professional Jewish scribe, contains an excerpt from the Book of Deuteronomy that commands the Jews to hang these words on the doorposts of their homes.
Shin on mezuzah
Many mezuzah cases are adorned with the Hebrew letter Shin, which stands for “Shaddai,” one of G-d’s holy names.
Why does a mezuzah have a Shin on it? The reason for the Hebrew letter Shin on a mezuzah is a reference to the holy name Shaddai, which itself is an acronym for Shomer Daltot Yisrael, "Guardian of Israel's doors". The Shin on a mezuzah therefore refers to G-d’s protection and guardianship over our homes.