In Biblical Hebrew, the word mezuzah means doorpost.1 The verse instructing us to write a mezuzah reads, “You shall write [these words] upon the mezuzot—doorposts—of your house and upon your gates.”2 Talmudic literature applied the term to the scroll affixed to the doorpost, which is how we still refer to it.A mezuzah must be written on the parchment of a kosher animal. The parchment must have been prepared explicitly for use as a sacred object. The words must be handwritten by an expert scribe well-versed in the intricacies of the script and its laws. Even the ink and quill are custom made to meet the necessary requirements.Mezuzahs should be checked by a certified scribe twice every seven years to see if they have been affected by adverse weather conditions, or by folding (which can cause cracks in the letters), or if any other defects have occurred. Some check their mezuzot every year, during the Hebrew month of Elul.While all mitzvot are performed to fulfill G‑d’s command, affixing a mezuzah to the doorway of your house has the added benefit of initiating Divine protection on the home and its inhabitants. Per the Talmud: “A king of flesh and blood sits inside [his palace], and his servants guard him from the outside. With G‑d, by contrast, His servants sit inside [their homes], and He guards them from the outside.”The tradition in many Jewish homes is to place one’s hand on the mezuzah when passing through the doorway, and there are those who then kiss that hand.