How to Install a Mezuzah?

Many ask – how do you put a mezuzah on the door? How do you install a mezuzah? The answer is that the mezuzah is placed on the right side of the entrance opening to the room or house, in the upper third of the doorframe side. Sephardim customarily affix the mezuzah upright, while Ashkenazim and Moroccan Jews tend to tilt it slightly diagonally. And if someone installed the mezuzah on the left side of the opening – it is invalid (Shulchan Aruch Yoreh De’ah 288:7) and must be removed from the left side and affixed again on the right side.

And it must be firmly attached to the right side of the opening so that the mezuzah does not fall off, for example with nails or glue. Before affixing the mezuzah, one should recite the blessing: “Blessed are You, LORD our God, King of the Universe, who has sanctified us with His commandments and commanded us to affix a mezuzah.” Even if affixing several mezuzot, one blessing suffices for all.

It is necessary to study the laws in order to know in which room a mezuzah must be installed and in which it is exempt. For only a doorway that has two doorposts and a lintel, and that opens to a room measuring four cubits (192 cm) by four cubits, requires a mezuzah. There are cases where the doorway is exempt, or where a mezuzah is required but without a blessing upon affixing. Therefore, if it is unclear, one should always ask a rabbi or someone knowledgeable in Halacha about each case.

Why do we put the mezuzah on the right side and not on the left side?

The reason for placing the mezuzah on the right side of the entrance from the perspective of someone entering the house or room, and not on the left side, originates from the holy Gemara’s interpretation of the verse “And you shall write them on the doorposts of your house,” where there is an implication of “your entrance,” meaning the mezuzah should be affixed on the side through which one “enters” the house.

What is ‘Shaddai’ on the mezuzah? Why is the mezuzah installed with ‘Shaddai’ facing outward?

A mezuzah consists of a mezuzah parchment + a mezuzah case. What is written in the mezuzah? That is, what is written on the mezuzah parchment? The main part of the mezuzah is a parchment sheet made from the skin of a pure animal, upon which a Sofer STaM (an abbreviation for Torah Scrolls, Tefillin, Mezuzot) writes in a special script called STaM script 2 paragraphs – “Shema Yisrael” and “Vehaya Im Shamoa,” and this mezuzah parchment is rolled from the end to the beginning and placed into an elongated box called a mezuzah case.

After clarifying what is written in the mezuzah, one must understand what ‘Shaddai’ in the mezuzah means, that is, why the name Shaddai (one of the names of the Holy One, Blessed be He) is written on the back of the mezuzah.

The reason ‘Shaddai’ is written on the mezuzah is because it is an acronym ש‘Mor ד‘Letot י‘Israel. It is brought in the Zohar (New Zohar Ruth, Part 2, page 25) that at the doorway where a mezuzah is affixed, no harm, no satan, and no severe damage approaches, because the Holy One, Blessed be He, guards the entrance, even at the time when permission is given to the destroying angel to harm, He raises His eyes and sees that there the name Shaddai is on the mezuzah standing at the entrance. It is also brought in the Zohar (Parashat Va’etchanan, Part 3, Resh Vav) that the name Shaddai on the mezuzah is effective only when the two aforementioned mezuzah paragraphs are properly written.

And in Rabbeinu Bachya (Parashat Va’etchanan) it is explained plainly that the reason why the name Shaddai is written on the mezuzah is because the nations of the world believe that the success of homes depends on the star system, and because the name Shaddai ‘plunders’ and overcomes the system, therefore the name Shaddai is written on the mezuzah – to hint that from Him the blessing and good enter the home, and not from the star system.

In the writings of the Arizal, of blessed memory (Sha’ar HaHakadmot, end of the Great Discourse regarding the Tree of Knowledge of Good and Evil, page 43), it is written that the secret of the verse “And Shaddai will be needed” means that the name Shaddai written on the back of the mezuzah stands there to protect against the ‘enemies’ and adversaries who are the kelipot so that they do not harm.

And it is necessary to affix the mezuzah so that the name Shaddai on the mezuzah faces outward, meaning the name Shaddai on the mezuzah should be visible from the outside while it is fixed in its place. However, this is only if it is a clean place; but in a place where there is a concern that something dirty or inappropriate might touch the mezuzah, it should be covered. There are those who do not have the custom for the name Shaddai on the mezuzah to be exposed from the outside, but rely on the letter Shin that is on the mezuzah’s exterior, and apparently the letter Shin is a remembrance of this (see on this matter in the book Shaarei Hamazuzah, chapter 15, footnote 19).