Mezuzah

A typical mezuzah on the doorpost of a home. The parchment is concealed within the external case.
Photo courtesy of www.retardstrength.net and Wikimedia Commons.
A mezuzah is a small waterproof box made of wood, metal, stone or ceramic, containing parchment inscribed with Hebrew text. It is affixed to the doorposts of Jewish homes and identifies them as such.
The parchment within the mezuzah is inscribed on the front with the words of Deuteronomy 6:4-9 and 11:13-21. On the back is written ‘Shaddai’, which means ‘Almighty’ and is one of the names of God, and an abbreviation for ‘guardian of the doors of Israel’. Shaddai or the Hebrew letter ‘shin’ is displayed on the front of the container or is otherwise visible through a hole. Kabbalistic symbols and inscriptions once appeared as an addition to the quotations on the parchment, to accentuate the protective mechanism of the mezuzah. 'Shaddai’, which appears on the back of the parchment, is a remaining example of this.
Historically, the mezuzah can be dated back to the time when the Jews were slaves in Egypt. All Egyptian houses had a sacred document at their entrance; Mezuzah literally means ‘doorpost’, hence it is placed on the doorpost of the Jewish home, as instructed in Deuteronomy 6:9 and 11:20: “inscribe them on the door-posts of your house and on your gates”.
Originally an abbreviated version of the daily prayer known as the Shema was carved into the doorpost of a Jewish home. This practice evolved into a piece of parchment with the 22 lines of the Shema written on it and tied to the doorpost. The Shema reinforces the Oneness of God. Later, a hollow reed was used to protect the parchment, which was finally developed into a container similar to the ones seen today.
Some people believe that the mezuzah serves as an amulet, to protect the home and to bring good luck. A more prevalent view of the significance of the mezuzah is that it doesn’t necessarily fortify us physically, but that it protects us against sinning by reminding us of God's commandments.
A 13th century Jewish scholar and physician named Maimonides claimed that the mezuzah served as a constant reminder that the affairs of the rest of the world were unimportant: “By the command of the mezuzah, man is reminded, when entering or departing, of God’s Unity, and is stirred into love for him. He is awakened from his slumber and from his vain worldly thoughts … This contemplation brings him back to himself and leads him on to the right path.”
According to Maimonides it was a distortion to believe that the mezuzah acted as an amulet, and that this detracted from its true meaning and purpose: “Fools pervert for temporal benefit the religious duty of the mezuzah, of proclaiming the Unity of God and the love and service due him…”
It is considered a religious duty to have a mezuzah displayed on the front doorpost of a Jewish home. It is a mitzvah (commandment) to make a mezuzah for someone else’s home, as a righteous act.
The mezuzah is one of many symbols in Judaism, which act as an identifier, a constant reminder of one's obligation towards God as well as an affirmation of the Unity of God.

