The fundamental importance of the mezuzah to Judaism is underscored by the story of Ruth, the grandmother of King David and archetype of all righteous proselytes. In explaining the laws of conversion to her, one of the first things her mother-in-law Naomi said was:

It is not the practice for daughters of Israel to dwell in a house that has no mezuzah.

Ruth replied:

Wherever thou lodgest, I will lodge; thy people shall be my people, and thy G‑d my G‑d.

Thus, in accepting the precept of mezuzah, Ruth accepted the G‑d of Israel and embraced her new nationhood.

In a simple sense, mezuzah is a reminder of the faith and the Unity of G‑d, as reflected in its content:

Hear O Israel, The L-rd is our G‑d, the L-rd is One.

So state Maimonides, Nachmanides, Sefer HaChinnukh, Ibn Ezra and other classical commentators.

The 613 commandments of Torah are generally classified in three categories: Chukim (statutes), Mishpatim (laws) and Edoth. The codifiers therefore place the commandment of mezuzah in the category Edoth – Testimonies.1

To be sure, there are other commandments in this category. The mezuzah is, however, the most ubiquitous. Other precepts in this category are limited by the time in which they apply, such as the Holidays which are by definition observed only in their appointed times, Tefillin which are donned only during the weekdays and not on Shabbath or Holidays, and Tzitzith which is mandatory only during the daylight, etc. Furthermore, Tefillin and Tzitzith are only obligatory to men after bar mitzvah, while women and minors are exempt from them. One of the most important mitzvoth, brith milah (the covenant of circumcision) is only applicable to men. The mitzvah of Mezuzah, on the other hand, applies to every Jew – man, woman and child, at all times (furthermore, according to some authorities, this is a unique commandment which one continues to observe even after he leaves his bodily existence ).

The Reminder

As one of the most visible and powerful symbols of Judaism, mezuzah serves as a reminder of the basic tenets of the Jewish faith.

Nachmanides2 and Sefer HaChinnukh3 point out that:

At the root of the mitzvah [of the mezuzah] lies the purpose that it should remind a person about faith in G‑d every time he [or she] enters the home or leaves it.

One of the earliest Jewish philosophers, Abraham ibn Ezra4, in his treatise on the philosophy of mitzvoth Sefer Yesod Morah Ve-Sod Ha-Torah, gives a similar rationale for the precept of mezuzah as a reminder to observe all religious precepts. He writes:

The reason Scripture gives for tzitzith (fringes) is, ‘you may remember and do all My commandments’ (Numbers XV, 40) when you constantly look upon the tzitzith (Numbers XV, 39). The same applies to “And thou shalt bind them5... and thou shalt write them6 [on the doorposts]” (Deuteronomy VI, 8-9).

Thus, according to ibn Ezra, a mezuzah (just like the tzitzith and tefillin) serves as a reminder to fulfill all commandments.

The great codifier of Jewish law Maimonides7 writes:

Every Jew must be extremely scrupulous in observing the mitzvah of mezuzah since it is a permanent obligation on him. Every time a Jew enters or leaves the house, he is faced with the Name of G‑d, with proclamation of the Unity of G‑d; he reminds himself of his love for Him. He awakens from his slumber, from being engrossed in vanities and follies of the passing hour, and he realizes that there is nothing permanent or eternal, save the knowledge of the Rock of the Universe. He then returns to the righteous path.

Derekh Chayim likewise connects mezuzah with remembrance of G‑d:

Every time you come in and go out, kiss the mezuzah so that you may remember G‑d.

Similarly, Rabbi Gedaliah of Lunietz8 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. When we enter our home, we are reminded by it to struggle against the impulses towards wrong conduct, and to avoid anger and quarrelsomeness. When we leave our home, we are again reminded by it to curb our egotism in dealing with our fellow-creatures, and in striving to acquire substance.

Declaration of Faith

Nachmanides writes in his commentary on Exodus

He who buys a mezuzah for one zuz (a silver coin) and affixes it to his doorpost and has the proper intent of heart on its content, has already admitted the creation of the world, the Creator’s knowledge and His Providence, and also his belief in prophecy as well as in all fundamental principles of the Torah...

Similarly, Rabbeinu Bachya9 states:

Therefore we are commanded to write in the first section of the mezuzah the subject of G‑d’s Unity and the obligation to study Torah, and in the second section, the veracity of reward and punishment. These topics attest and signify three things: the truth of prophecy, the creation of the world, and Divine Providence, as the remembrance of the Exodus from Egypt, which was replete with wonders, obliges one to arrive at the above principles and to attest to their truth. Thus, when one buys a mezuzah and affixes it in the doorway through which he enters and leaves his home, he demonstrates thereby his approval and admission of belief in these three principles, which constitute the essentials of the Jewish faith and the Torah.

A Dwelling Place for G‑d

Rabbi Samson Rafael Hirsch10 writes about mezuzah:

The Biblical passages Shema and Vehayah should be written upon the entrance of every house, thereby hallowing the house (and indeed every place specially set aside for human activities) as an abode where G‑d is ever present and where the service of G‑d is fulfilled; thus testifying that all one’s life, all that one endures is accomplished through G‑d – your deeds as a striving to G‑d; and your burden – namely, all that happens to you in life, as emanating from G‑d. That is the lesson of the obligation of mezuzah... It teaches you the meaning of domestic life and dedicates your house as a temple of G‑d and your whole way of life as a service of G‑d... When you enter your house, put your hand upon the mezuzah and remind yourself that you are treading upon consecrated ground. When you leave your house, put your hand upon the mezuzah and commit your house to the protection of Him to Whom it is dedicated.

Mezuzah is the symbol of a Jewish home. Positioned at the doorpost of the house entrance exposed to the outside, the mezuzah separates the house from the outside world as a Jew’s inner sanctum and marks it with the sign of holiness.

Blessed shalt thou be when thou comest in, and blessed shalt thou be when thou goest out. (Deuteronomy XXVIII, 6).

As the Zohar puts it:

Just as the body of a Jew is marked by the holy sign of circumcision (Brith Milah), his garment is marked by tzitzith, so is his house marked by mezuzah.

Rabbi Joseph Isaac Schneersohn11 said:

Just as performance of the mitzvah of mezuzah – writing two chapters of Shema and placing them by the house entrance – turns the house into a vessel of G‑dliness, so it is of all the other mitzvoth – whatever they touch, they turn into vessels of G‑dliness.

Mezuzah turns a Jewish home into a sanctuary, a place in which G‑d dwells. The Midrash teaches that the primeval impetus of Creation was the desire of the Holy One to have a dwelling place in the lowest worlds. In other words, the Creator desired that mankind, through its divine service, should transform and refine the coarse physical world (the lowest of all worlds) to reveal its G‑dly nature, so that G‑d may be openly revealed (“dwell”) within the creation. In consecrating the house as G‑d’s dwelling place, mezuzah thereby brings about realization of the ultimate purpose of Creation. Thus, the arrow of mezuzah not only points to the innermost purpose of creation, but mezuzah, as all of the Mitzvoth it comes to symbolize, actually fulfills this purpose and brings about its ultimate realization.

Sign of Love

The L-rd preserveth all them that love Him...

Psalms 145:20

The mezuzah is a sign of eternal love of G‑d toward His chosen nation, as it is said:

G‑d so loved Israel that He surrounded them with mitzvoth: tefillin on the arm and head, tzitzith on their garment, and a mezuzah on their door.

Similarly,

Every single Jew is surrounded by seven mitzvoth. He has tefillin on his arm and head, a mezuzah on his door, and four tzitzith on his garment. Thus, King David sang in his Psalms: ‘I will praise You each day with seven.’ (Psalms CXIX, 164)

In the Song of Songs, the poem of the eternal love affair between G‑d and Israel, the bride (an allegory for the chosen nation) says:

Let his left hand be under my head [and his right hand embrace me.]12 (Song of Songs II, 6.)

Says the Midrash:

This refers to the mezuzah. R. Yohanan derives evidence from the verse “To love the L-rd thy G‑d and to cleave unto Him” (Deuteronomy XI, 22) And what is this cleaving? It is with “His left hand under my head”

And the groom (an allegory for the G‑d of Israel) says:

I have compared thee, O my Love, to a steed in Pharaoh’s chariots. (Song of Songs I, 9).

A Midrash connects this verse with another verse in Torah:

At His right hand [was] a fiery law unto them... (Deuteronomy XXXIII, 2) while “and on their left hand” refers to the mezuzah.

In the Song of Songs we find other allusions to the mezuzah as a symbol of love between G‑d and his chosen people.

Behold thou art fair, my beloved, behold thou art fair. (Song of Songs IV, 1)

The first part of this verse, explains the Midrash, refers to the mezuzah, while the second part, to the phylacteries, as if G‑d says to His beloved people:

Behold thou art fair with the mezuzah,

Behold thou art fair with the phylacteries.

And further,

How fair and how pleasant art thou. (Song of Songs VII, 6)

The Midrash explains:

How fair art thou with the mezuzah and how pleasant art thou with the phylacteries.

The mezuzah serves as the symbol of eternal love between G‑d and Israel, as a medium through which one can cleave to G‑d and achieve a profound sense of intimate closeness with the Creator.

Holier than Torah?

Mezuzah and a Torah Scroll

In Halakhah, Jewish ritual law, a Torah scroll, according to majority opinion, has higher sanctity than a mezuzah. Nonetheless, from a certain point of view, perhaps, one may say allegorically that a mezuzah has higher sanctity than even a Torah scroll.

The Talmud states that there is no difference between Torah scrolls, on the one hand, and tefillin and mezuzoth on the other, except that a Torah scroll may be written in any language [and script], whereas tefillin and mezuzoth may be written only in the Holy Tongue – Hebrew – and in the square Ashurith script. This perhaps implies that the mezuzah as well as the tefillin has, in a way, a higher sanctity than the Torah scroll.13

Korach’s Question

One can further deduce this from the biblical account of Korach’s argument with Moses (Numbers XVI):

Korach asked Moses, “If a house is full of Torah scrolls, what is the law? Should it be exempt from the obligation of having a mezuzah?” Moses replied, “It is still under the obligation of having a mezuzah.” Korach retorted, “The entire Torah cannot exempt a house, but the two sections [of the Torah] in a mezuzah can?”

The simple explanation of the apparent paradox to which Korach pointed lies in the fact that a mezuzah is not merely a short excerpt from the Torah but a mitzvah in its own right, from which even a complete Torah scroll can not exempt one.

The Kotzker Rebbe14 notes that the Korach’s question may be rephrased allegorically:

Is a scholar who understands the reasons for the commandments free from the obligation of actually observing them? Moses answered him that a learned scholar was equally obligated to observe the commandments.

Referring to the story of Korach, the late Lubavitcher Rebbe, Rabbi Menachem M. Schneerson, points out that the entire house may be full of seforim (sacred Jewish religious books) and yet its inhabitants may fail to reflect on the sacred content of these books. The central concept of the mezuzah, on the other hand, is the constant mindfulness of the ideas expressed therein. Entering the house from the street, leaving home, moving from room to room – a Jew, while touching the mezuzah, is constantly reminded of his obligation to be mindful of the L-rd, our G‑d, who is One. Furthermore, this mindfulness must find its expression in serving G‑d “...with all thy heart, and with all thy soul, and with all thy might.” Ultimately, these must be expressed in “if you shall carefully obey my commandments...” written in the second portion of the mezuzah. Even if a person has received an excellent Jewish education – he is “full of Torah books” – he needs to “affix a mezuzah”, stresses the Rebbe, to the doors of his heart and intellect so that his heart and mind reflect the ideas expressed in the mezuzah in a real way.

The third Lubavitcher Rebbe, the Tzemach Tzedek, compares the mezuzah on the outside and the Torah scrolls inside respectively to the two sets of keys – the outside keys and the inside keys. When the outer keys are not there, there is no use for the inner keys.

Mezuzah and Tefillin

Rabbi Isaiah Horowitz, the Shelah15, writes:

Performance of different commandments represents allusion to varying levels of our attachment to the Hereafter. In this regard, the act of affixing a mezuzah ranks higher than donningtefillin.

Furthermore, while Torah may be taught to Gentiles, according to Radbaz16, they are prohibited from donning tefillin and affixing mezuzoth. These commandments, as we have already seen, mark the special sanctity of the nation of Israel. Only in the messianic era, when all the nations will be purified, will Mashiach (the Messiah) come to teach Gentiles the mitzvoth of mezuzah and tefillin.