The L-rd is thy keeper; the L‑rd is thy shade upon thy right hand

Psalms CXXI, 5

In the Bible

The word “mezuzah” appears for the first time in the Bible in the account of the Exodus from Egypt. Before the last plague smiting the Egyptian firstborn, the Almighty forewarned the Jewish people to mark their doorposts with the blood of the sacrificial lamb so that the forces of destruction would pass over their houses. The Torah says:

And they shall take of the blood and they shall put it on the two mezuzoth (doorposts) and on the lintel... For the Lord will pass through to smite the Egyptians, and when He seeth the blood upon the lintel, and on the two doorposts, the Lord will pass over the door, and He will not allow the destroyer to come in unto your houses to smite [you]. (Exodus 12:7, 23)

This is why the Holiday of the Exodus is called Passover. The Mechilta 1 (as well as the Zohar) states that these verses are the source of the concept of mezuzah:

Now consider: The blood of the Passover sacrifice was but of little weight, for it was required but once, not for all generations, and by night only, not by day; yet He would ‘not allow the destroyer... to strike you.’ How much more will He not permit the destroyer into the house which bears a mezuzah, which is of greater weight, seeing that the Divine Name is repeated there ten times, it is there by day and night, and it is a law for all generations.

We see in this biblical account and the above commentary the direct relationship between the mitzvah of mezuzah and Divine protection. A mezuzah affixed to the doorpost as commanded by G‑d at Sinai still has the power to “not allow the destroyer to come into your houses to smite you”. Indeed, immediately after the commandment of mezuzah, the Torah continues

... so that your days may be multiplied, and the days of your children... (Deuteronomy XI, 21)

This verse is the biblical source of the firm belief in the power of the mezuzah to protect from harm and to prolong one’s life.

Furthermore, the Torah lays down the law that:

a man that hath built a new house and hath not dedicated it, let him go and return to his house lest he die in battle... (Deuteronomy (XX, 5).

The Torah fears for the life of a soldier who has not yet affixed a mezuzah to his house and is thus deprived of its protection.

The Bible also alludes to the protective power of mezuzah in yet another place:

It is written, “And the waters were a wall to them on their right hand and on their left.” (Exodus XIV, 29). The mezuzah forms a wall to Israel’s right, and the tefillin to their left.

It further states:

The Eternal is your guardian; the Eternal is your shade upon the right hand. (Psalms 121:5).

In the Talmud

The mezuzah helps us remember that the true owner of our house is the Master of the Universe, and we, along with our families and belongings, are merely guests in His world. Thus, it is written:

If a man affixes a mezuzah, did I not give him the house?

As a host par excellence, He stands outside the house and guards His guests and their belongings.

Let us turn again to the Talmudic narrative about the Parthian King Ardavan and Yehudah HaNasi (see The Knowledge of G‑d [2nd paragraph]). As the narrative continues, the King’s daughter later fell ill (in the words of the Talmud she was possessed by a demon). The court’s physicians failed to relieve her condition. Ardavan, remembering the words of the Jewish sage, ordered that the mezuzah be affixed to the doorpost of the princess’s room, whereupon she was immediately cured.

This and the following talmudic aggadah (narrative) serve as evidence that the belief in the protective powers of mezuzah is not a superstition or an invention of medieval kabbalists, as some critics would have us believe, but is deeply rooted in the Talmudic and Rabbinical Judaism.

A well-known story from the Talmud involves a famous ger (proselyte, convert), Onkelos2 the son of Kalonymos, a nephew of the Roman Emperor Titus:

When Titus, outraged by the conversion of his nephew to Judaism, sent his advisors to try to persuade him to return to the Roman religion, Onkelos was so convincing in his argument that all of the Emperor’s envoys became proselytes themselves. Caesar then sent legionnaires to arrest Onkelos and instructed them not to engage in any conversation with his nephew. When the legionnaires escorted Onkelos out of his home, he smiled and placed his hand on the mezuzah. Observing the bewildered soldiers, Onkelos explained that a mortal king has servants standing outside his house on guard. The King of Kings, however, is Himself guarding His servants outside their homes. As King David sang in his Psalms: “G‑d shall guard thy going out and thy coming in from now and forevermore.” (Psalms CXXI, 8). These words made such a profound impression on the legionnaires that they too converted to Judaism.

The Lubavitcher Rebbe, Rabbi Menachem M. Schneerson, points out the instant effect the mezuzah had on the Roman soldiers. The Rebbe explains that this quality is unique to mezuzah. It is said that tefillin have the power to induce fear in an enemy, but only the mezuzah can affect the soldiers of an evil empire instantaneously to become converts to Judaism – the antithesis of evil. This ability to have a profound and immediate effect on people is unique to mezuzah.

Another profound testimony to the protective power of the mezuzah is found in the Talmudic discussion of the laws pertaining to an Idol-Worshipping city, Ir HaNidachath. Torah law enjoins the Sanhedrin, the Supreme Court, to condemn such a town, with all its inhabitants and their belongings to total annihilation:

...Thou shalt surely smite the inhabitants of that city with the edge of the sword, destroying it utterly, and all that is therein... (Deuteronomy XIII, 16)3

However, the Sages of the Talmud teach:

No city containing even a single mezuzah can be condemned.

One mezuzah can save the entire idolatrous city from destruction!

An interesting illustration of the mezuzah’s power to protect one’s life is found in the Talmudic discussion wherein a rabbi asks if women are obligated by the mitzvah of mezuzah, and another rabbi answers with a rhetorical question:

Men have to live; do not women have to live as well?!

In the Law and Classical Rabbinical Writings

The Biblical notion of the protective powers of the mezuzah is reiterated in the Mishnah and elaborated on in the Talmud. It is further strengthened and elevated to Jewish law, Halakhah, in the Shulchan Arukh 4:

He who is careful and particular in the observance of mezuzah – his days and the days of his children will be lengthened.

Furthermore, the Code of Jewish Law rules that the mezuzah, aside from its reward of longevity for oneself and one’s children stated in the Bible, has the effect of guarding the house and its inhabitants from any harm. The Beth Yosef 5 calls this an open miracle.

Rabbeinu Bachya writes:

To impart in our hearts the principle that Divine protection pervades Israel at all times, day and night, the Torah has commanded us to place the mezuzah at the entrance of our homes. We will thus be cognizant of this principle of Divine protection whenever we enter a home, and we will be mindful that this protection is constantly with us. Even at night, His protection surrounds our house and protects us while we sleep.

He writes further:

G‑d is called “The Guardian of Israel,” as it is said, “Behold, He that guards Israel neither slumbers nor sleeps.” (Psalms 121:4). Since G‑d is supreme above all and rules over the six ends [of the universe, i.e., above, below, east, west, north, and south], the psalmist mentioned the expression ‘guarding’ six times in that psalm.6

Ibn Ezra writes:

In time of trouble, G‑d saves those who serve Him out of fear. However, G‑d protects those who serve Him out of love, from encountering trouble.

Mezuzah, a sign of eternal love between Israel and the Creator, therefore prevents any trouble from entering a Jewish home.

The Lubavitcher Rebbe, Rabbi Menachem M. Schneerson, explains that, unlike other mitzvoth, such as honoring one’s parents, for which the Torah promises longevity, the protection afforded by the mezuzah is not a reward for the mitzvah but rather an immediate and essential result of its observance, as the Sages teach us that:

The very purpose of mezuzah is the protection of the house and its inhabitants.

In the Kabbalah

The principal book of Kabbalah, the Zohar, states that if a Jew affixes a mezuzah to his or her door, the Almighty denies harmful and destroying agents (mazikin) any access to the home, even at a time when the Destroying Angel is let loose.

Recanati7 writes similarly, “The mezuzah affixed to the doorpost of a home serves as a protection against the messengers of evil. When confronted by the name of G‑d, which is on the exterior of the mezuzah, these messengers of harm realize that G‑d is watching over this domicile and they will refrain from entering. The word mezuzoth is a combination of the words ‘zaz’ and ‘maveth’ which mean literally: Death: Remove thyself.”

Expounding on the verse “G‑d shall guard thy going out and thy coming in from now and forevermore,” (Psalms 121:8) the Zohar explains that the mezuzah protects the inhabitants of the house not only in their home but also from the time they leave the house until they return home: “Not only is a man protected in his house, but G‑d protects him both when he goes out and when he comes in, as it is written, ‘G‑d shall guard thy going out and thy coming in, etc.’”

This idea reverberates through the writings of many early and later sages (Rishonim and Acharonim). Thus, for example, Sefer HaBaith quotes Kitzur HaShelah, which in turn relies on Shaarei Tzion in stating that the mezuzah protects the inhabitants of the house from the harm not only when they are in the house, but also when they leave the house.

And similarly: “G‑d says to Israel: ‘Many are the accusers looking out for you, but be diligent in my service and I will protect you without, while within you will sleep safely in your beds.’”

It says further: “When a man ...puts the tefillin (phylacteries) with the holy impress on his head and his arm, and he covers himself with tzitzith (fringed robe), and as he issues from the door of his house he passes the mezuzah containing the imprint of the Holy Name on the doorpost, then four holy angels join him and issue with him from the door of his house and accompany him to the synagogue and proclaim before him: Give honor to the image of the Holy King, give honor to the son of the King, to the precious countenance of the King. A holy spirit rests on him and proclaims: ‘Israel in whom I will be glorified’ (Isaiah XLIX, 3), and then ascends aloft and testifies concerning him before the Holy King. Then the Most High King orders the names of all the children of His palace, of all those that acknowledge Him, to be written before Him, as it says, ‘And it was written in the book of remembrance before Him, for them that feared the Lord and that esteem His name’ (Malakhi III, 16).”

This last phrase in the Zohar is in striking parallel with the words of Daniel prophesying about the apocalyptic war of Gog and Magog: “At that time, your people will be rescued, all who are found inscribed in the book.” (Daniel XII, 1)

The ability of the mezuzah to protect inhabitants of the house finds its expression in a number of kabbalistic customs. The holy name of G‑d, Shad‑dai 8, is written on the back of the parchment. This name consists of three letters: Shin, Daleth and Yud, which comprise an acronym “Shomer Delathoth Yisrael – Guardian of the Gates of Israel.”

As we have noted earlier, Rabbi Gedaliah of Lunietz writes:

We find inscribed on the outside of the mezuzah the letters Shin, Daleth and Yud. This word is used because it also comprises the acronym of “Shomer Delathoth Israel” – The Guardian of the doors of Israel. It is commanded that the mezuzah shall be affixed to the doorposts of every Jewish house, serving as a visible symbol of G‑d’s protection over the house.

According to the mystical teachings of Kabbalah, the name Shad-dai has the power to repel forces of evil. The Zohar states:

Now, when the forces of evil (demons) come to the door of a man’s house, they raise their eyes and see the Holy Name written outside the mezuzah, namely Shad-dai, which has power over all of them, they flee away in fear of it and do not come near the door.

Rabbi Gikatilla writes:

When this attribute is called Shad‑dai all destructive forces are dispersed. This is the ultimate meaning of the verse in the Psalm of Demons “O thou that dwellest in the cover of the Most High, and abidest in the shadow of Shad‑dai.” (Psalms XCI, 1) When it is called Shad‑dai it dresses as a consuming black fire from which all destructive demons flee and legions of impure creatures do not have the strength to withstand [its consuming flame]. All are dispersed and reduced to piles of ashes.

The Sages say that this Name is alluded to in the verse:

And all the peoples of the earth shall see that Name of the L‑rd is called upon thee; and they shall be afraid of thee. (Deuteronomy XXVIII, 10)

Therefore, the mezuzah is placed in its case in such a way that this Holy Name (or at least its first letter Shin) is visible. If the case is not transparent, an aperture is made in it so as to expose the name Shad-dai. Otherwise, this Name or the letter Shin is painted or engraved on the case.

The Zohar states that wherever this holy Name is written, the evil forces are powerless. Furthermore,

...When a Jew affixes to his door a mezuzah in which the Holy Name is inscribed, the Master of the Uni­verse crowns him with His crowns, and no forces of evil can come close to the gates of his house.”

Thus, it is written:

These are the gates of G‑d; [only] the right­eous shall enter therein. (Psalms 118:20).

The Zohar further expounds, saying:

...As for the evil spirit that abides between the doorposts, woe to the man who does not know how to guard it by impressing on the door of his house the Holy Name that it may be with him.

Chasidic sources are abundant with references to mezuzah as a protection against forces of evil. The Tzemach Tzedek writes:

The mitzvah of mezuzah is called the guardian of man as it protects him and his household from the damage and accusations from the Chitzonim (forces of the outside - evil).

The notion of protection from mazikin (destroying agents, demons) is not limited to Kabbalistic literature, but is also found in the classical exoteric rabbinical sources. Thus Mordekhai9 writes in the name of Maharam10:

A mazik (demon) cannot rule on any house that has a kosher mezuzah as required by Jewish law.

There are ten holy Names of G‑d which denote various modes of Divine manifestation or modes of expression in which G‑d relates to His Creation. These ten Names correspond to the Ten Sefiroth, Divine Emanations.

Rabbi Moses Cordovero11 writes:

Before we go into an explanation of the details of the Divine Names, we must provide an introduction to their overall significance. Looking at many of them, one sees only incomprehensible combinations of letters, without any discernible meaning, and most of them are also unpronounceable. When an intelligent person sees such things, he can think that these names have no rational basis, and even that they involve nothing more than childish superstition, heaven forbid. We therefore have an obligation to warn the reader not to make this basic mistake.

Actually, the truth concerning these names is just the opposite. They can bring to the highest states, since they are all engraved in the loftiest spiritual realms. Their source reaches up through the steps of the Ladder, level by level, until it reaches the place where they express the essence of the Sefiroth and their spiritual nature.

The souls of the letters used in these Names are the substance of the Sefiroth, in their internal essence. The Name designated for each one is a garment for that Sefirah. It is for this reason that the Names [associated with the Ten Sefiroth, which are the Names that the Bible uses for G‑d,] may not be erased or destroyed.

Among these Divine Names are the Tetragrammaton, the proper ineffable Name of G‑d - YHVH (pronounced in the vernacular as Havayah), and Shad-dai (pronounced in the vernacular as Shakkai) – usually translated as the Almighty. While the Tetragrammaton expresses the absolute unity of G‑d who is utterly beyond time and space, the Name Shad-dai denotes the multiplicity of the Creation. As the Sages point out, this name comes from the Hebrew root dai - enough, as in the famous Passover song Daiyenu (It Would Have Been Enough for Us). Shad‑dai, in this context, is interpreted as She Dai – that it suffices, “which tells that there is enough, there is completeness, there is fullness”.

By saying daienough, G‑d, as it were, sets the boundaries of various levels of Creation, thereby creating multiplicity. Thus it is written:

He set the borders of the peoples... (Deuteronomy XXXII, 8)

And also:

And it is they that are the boundaries of the Universe.

The multiplicity of the world disguising the true underlying unity of the Creation is the ultimate source of evil. Thus, the holy Name that is the source of multiplicity has the power over evil, which stems from multiplicity.

It is interesting to note that the law instructs that the Name Shad-dai be written exactly opposite the word Vehayah - and it shall come to pass, the first word of the second Torah paragraph inscribed in the mezuzah scroll. Rabbi Gikatilla writes:

Since this attribute is the gateway to the name YHVH, the name Shad‑dai is on the outside of the parchment affixed to one’s doorpost. The name [Shad‑dai] is positioned adjacent to the chapter Vahayah Im Shamoa. The juxtaposition of Shad‑dai to the aforementioned chapter is alluded to in the verse, “Vehayah Shad‑dai (and the Almighty be) thy treasure.” (Job XXII, 25)

The word Vehayah has exactly the same letters as the Tetragrammaton: YHVH. Thus, the structure of the mezuzah reflects the structure of the ultimate reality: the transcendent and absolute nature of the Creator expressed by His proper Name Havayah (as alluded to in the word Vehayah) is hidden behind the apparent multiplicity of the Creation as it is expressed by the Name Shad-dai. Therefore, in the words of the Zohar, the mezuzah wards off demons, which, according to Maharal12, represent the powers of many that oppose the power of One. In the word Vehayah - and it will be, the Torah promises us that if we meditate upon this profound concept and follow the path outlined in the paragraphs Shema and Vehayah, than we will discover behind the disguise of the physical world G‑dliness and the true and ultimate Unity.

In the story of the Exodus, G‑d told Moses:

I appeared unto Abraham, unto Isaac, and unto Jacob, as G‑d Almighty (Shad‑dai) (Exodus VI, 3).

The classical commentator Keli Yakar 13 suggests that the use of the name Shad‑dai in this context implies that G‑d said, as it were, “Enough!” putting a limit to the suffering of the Jewish people in exile. The same Name written on the mezuzah continues to help to keep suffering at bay within the Jewish home.

Some Tzadikim14 used to meditate at the mezuzah on the name Shad‑dai or on other lofty concepts. Reb Elimelekh of Lyzhansk used to meditate on the name Shad‑dai on the mezuzah in order to fulfill the verse

I have set G‑d before me always. (Psalms XVI, 8)

Yitzhak Buxbaum reports that Kav HaYashar suggests meditating on the name Shad‑dai after kissing the mezuzah. He also cites the following account about Rabbi Eleazar Zev of Kretchnif:

In the morning, on his way to the synagogue, he would stand by the mezuzah of his house for some time in meditation, and so also at the mezuzah of the Beith Midrash.

As we find explicit references in the literature of use of the mezuzah as a meditative device (loc. cit.), we may speculate that the reason that the name Shad-dai was usually exposed through an aperture in the case had something to do with the use of the Divine Names in Kabbalah for meditative purposes. Since the mezuzah case is not a barrier (as long as it is not made from metal, according to some authorities; see below section “The Case” on p. 130) to the protective spiritual forces emanation from the Divine Name Shad‑dai inscribed on the mezuzah, we may speculate that this Name was traditionally exposed through an aperture in the case in order to make it physically visible to the beholder. This way, one might meditate on the Name or even silently pronounce it as he passed by the mezuzah. As we said before, most of the Divine Names (including the name Shad‑dai) may not be pronounced outside of strictly regimented conditions. However, Kabbalists frequently used a technique of “swallowing the Name,” i.e., pronouncing it silently. Rabbi Moses Cordovero states that:

If one wishes to pronounce the Name (having attained all prerequisite levels of asceticism and piety – AP) he should do so with his mouth closed, so that no air should leave his mouth. It should not be voiced at all, but only mouthed with the larynx and tongue. Among initiates, this method is known as “swallowing” the Divine Name.

A similar technique might very well have been used with the name Shad-dai in the case of mezuzah.

In the Middle Ages, when practical (magical) Kabbalah was especially popular, the mezuzah was treated by some as an amulet. This expressed itself in kabbalistic inscriptions on the parchment with the names of Angels and hexagrams. Many rabbinical authorities of that time looked tolerantly on such practices. Thus, Rabbi Eliezer b. Samuel of Metz15 reports that:

[It is a] common practice to add seals and the names of certain Angels at the end of the Bible verses contained in the mezuzah for the sake of the increased security of the home. This is neither commanded nor prohibited; it simply serves as additional protection.

A mezuzah from Elkanan Adler’s collection, as it is reported by Gershom Scholem, has up to twelve hexagrams. Some mystically minded authorities even insisted on such additions to the mezuzah.

However, when this practice fell into such abuse that various names and seals were actually inserted in the text of mezuzah between the biblical verses, thereby halakhically 16 invalidating the mezuzah, Maimonides rose to strongly oppose such practices. He wrote:

It is a common custom to write [G‑d’s name,] Shad‑dai, on the outside of a mezuzah opposite the empty space left between the two passages. There is no difficulty in this, since [the addition is made] outside.

Those, however, who write the names of angels, other sacred names, verses, or forms, on the inside [of a mezuzah] are among those who do not have a portion in the World to Come. These fools not only nullify the mitzvah, but furthermore, they make from a great mitzvah ([that reflects] the unity of the name of the Holy One, blessed be He, the love of Him, and the service of Him) a talisman for their own benefit. They, in their foolish conception, think that this will help them regarding the vanities of the world.

As great as the protective power of mezuzah is, we observe this mitzvah as any other commandment of Torah, simply because it is G‑d’s will. We affix a mezuzah to our doorpost not because it will protect us, though it certainly will, but because G‑d commands us to do so in His holy Torah.

It must be clarified that Maimonides did not dispute the protective property of the mezuzah, nor did he object to the auxiliary use of it for this purpose alone, as was the practice during the time of Mishnah, and sometimes even now. He strongly objected to practices that halakhically invalidated the mezuzah by inserting extraneous writings in the text of the mezuzah, which must be exactly as it appears in the Torah, whatever the purpose of these writings may be. Furthermore, he objected to the degrading view of the mitzvah of mezuzah as a mere amulet, since this mitzvah, though its main purpose is protection, is nonetheless infinitely richer in its multifaceted significance and manifold meaning.

The literature of Kabbalah and Jewish folklore abound with the stories of gilgulim (transmigration of souls, metempsychosis), dibbuks (possession by spirit), and exorcism. A common practice has been to prevent a spirit or a wandering soul from entering the house or its inhabitants by placing mezuzoth at the doors. In one well-documented account, Rabbi Isaac Luria (the Ari-zal)17 sent his disciple Rabbi Chayim Vital18 to investigate a case of a dibbuk, and instructed him to check the mezuzoth. It turned out that the house lacked mezuzoth altogether. Upon affixing mezuzoth the spirit stopped appearing.

In ancient times it was a Jewish custom recorded in the Mishnah, Talmud and Midrash to carry a mezuzah in a walking stick for protection. It was customary among Sefardic Jews to take a mezuzah parchment to a courthouse during a trial and to give it to women in labor. Nowadays, these customs are alive in Sefardic and Chasidic communities. The sixth Lubavitcher Rebbe, Rabbi Joseph Isaac Schneersohn, used to keep a mezuzah on his desk at all times. His daughter, Rebetzin Chaya Moushka, the wife of the seventh Rebbe of Lubavitch, Rabbi Menachem Mendel Schneerson, used to keep a mezuzah in the glove compartment of her car. The Rebbe himself kept a mezuzah on the desk during private audiences. If an audience was to take place outside his office, the Rebbe would be sure to take a mezuzah with him. Apparently, this tradition goes back to the first Chabad Rebbe, Rabbi Schneur Zalman of Liadi, “who always had a mezuzah lying near him to look at in order to remember G‑d, as it is written:

I have set G‑d before me always. (Psalms XVI, 8)”

In one of the Rebbe’s letters, he recommends to his correspondent, who complained of nightmares, to keep a kosher mezuzah near her bed. To another correspondent suffering from migraines, the Rebbe suggested that she keep a kosher mezuzah wrapped in a cloth with her at all times (besides Shabbath when carrying outside is prohibited) promising that it would improve her health.

It is easily understood that a non-kosher mezuzah does not possess any protective qualities. Therefore when, G‑d forbid, someone is sick or some other misfortune befalls, the very first thing (after calling 91119) is to check the mezuzoth in the house. This has been Jewish custom from time immemorial. If some of the mezuzoth turn out to be non-kosher or their status is in doubt, they should immediately be fixed if possible, or replaced by new kosher mezuzoth.

Countless stories are told and retold in Jewish folklore about people who became well, regained lost jobs, and about barren women who became mothers, after fixing or replacing non-kosher mezuzoth. Some of these stories have been documented and published.