The klaf and its parchment

The heart of the mezuzah is the klaf, a small piece of parchment prepared from the hide of a kosher animal and specially processed for sacred writing. On it a trained scribe (sofer) hand-writes two passages from the Torah in black ink, using a quill and the traditional Assyrian script (ktav Ashuri).

The scroll is rolled from left to right so the text faces inward, and the word שַׁדַּי (Shaddai, a Name of God) is often written on the reverse, visible through the case's small window. The case protects the klaf; the klaf is the mitzvah.

The Shema

The klaf contains two paragraphs of the Shema, Deuteronomy 6:4–9 and 11:13–21, the declaration of God's oneness and the command that places the mezuzah on the doorpost in the first place. It opens with Judaism's central verse:

Every letter must be present, in order, and legible. It is these exact words, not the design of the case, that make the object holy.

What makes it kosher

A printed or photocopied scroll is never kosher. Only a hand-written klaf that meets every requirement is valid.

• Written by a qualified sofer.A trained, observant scribe writes it by hand with proper intent (kavanah), in the correct order, on kosher parchment with kosher ink.
• Every letter complete and correct.No letter may be missing, broken, touching another, or out of shape. A single flawed letter invalidates the entire scroll.
• Checked by a certified examiner.Buy only from a reputable source, and have it verified. Scrolls should be checked twice in seven years, as letters can crack or fade.
• Rolled and stored correctly.Rolled from the end toward the beginning so שְׁמַע appears first when unrolled, and kept in a case that shields it from moisture and damage.

How and where to affix it

A mezuzah is required on the entrance and on nearly every interior doorway of a home, including living spaces and bedrooms, but not on bathrooms or very small rooms. Fix it firmly at both ends so it is attached to the doorpost, not merely hung.

The blessing when affixing

Recited immediately before fixing the mezuzah to the doorpost. When putting up several at once, one blessing covers them all.

Why we do it

The mezuzah comes directly from the words of the Shema: "And you shall write them on the doorposts of your house and on your gates." For millennia it has marked a Jewish home, a declaration of faith fixed to the threshold and passed each time one comes and goes.

Many touch the mezuzah and kiss their fingers on passing, a gesture of love and a reminder of God's presence carried from the doorway into daily life.