What is a mezuzah?

The commandment

The Torah says twice: “You shall write them on the doorposts (mezuzot) of your house and on your gates” (Deuteronomy 6:9; 11:20). The word mezuzah means doorpost; it came to mean the scroll itself. The scroll must be written by a qualified scribe (sofer) on kosher parchment, with ink and in the exact traditional script. Printed copies are not valid.

Where and how it is placed

The mezuzah goes on the right side of the doorway as one enters, in the upper third of the doorpost (Shulchan Aruch, Yoreh De’ah 289). Every door of a home that is used for living – not bathrooms – needs one. A blessing is said when fixing it: “…who commanded us to affix a mezuzah.” Ashkenazim place it at a slant, top pointing inwards; Sephardim fix it upright.

When and who

In one’s own home in the Diaspora, the mezuzah is put up when moving in; when renting outside Israel, the custom is to fix it within thirty days. Scrolls should be checked by a scribe twice in seven years, because letters can fade or crack.

Its meaning

Maimonides writes that whenever one enters or leaves and meets the unity of God written on the doorpost, one is reminded of what is eternal (Laws of Mezuzah 6:13). Many touch the mezuzah and kiss their fingers when passing. The sages see it as a sign of God’s protection of the home, but Maimonides warns against treating it as an amulet: it is a commandment, not a charm.