If I kiss it, will I find Prince Charming? The Many Meanings Hiding Behind the Mezuzah

For All Ages - Sesame Street

For Teens/Adults (Funny!) - HaYehudim Baim / The Jews are Coming

What's Inside?

(ד) שְׁמַ֖ע יִשְׂרָאֵ֑ל ה' אֱלֹקֵ֖ינוּ ה' ׀ אֶחָֽד׃ (ה) וְאָ֣הַבְתָּ֔ אֵ֖ת ה' אֱלֹקֶ֑יךָ בְּכָל־לְבָבְךָ֥ וּבְכָל־נַפְשְׁךָ֖ וּבְכָל־מְאֹדֶֽךָ׃ (ו) וְהָי֞וּ הַדְּבָרִ֣ים הָאֵ֗לֶּה אֲשֶׁ֨ר אָנֹכִ֧י מְצַוְּךָ֛ הַיּ֖וֹם עַל־לְבָבֶֽךָ׃ (ז) וְשִׁנַּנְתָּ֣ם לְבָנֶ֔יךָ וְדִבַּרְתָּ֖ בָּ֑ם בְּשִׁבְתְּךָ֤ בְּבֵיתֶ֙ךָ֙ וּבְלֶכְתְּךָ֣ בַדֶּ֔רֶךְ וּֽבְשָׁכְבְּךָ֖ וּבְקוּמֶֽךָ׃ (ח) וּקְשַׁרְתָּ֥ם לְא֖וֹת עַל־יָדֶ֑ךָ וְהָי֥וּ לְטֹטָפֹ֖ת בֵּ֥ין עֵינֶֽיךָ׃ (ט) וּכְתַבְתָּ֛ם עַל־מְזוּזֹ֥ת בֵּיתֶ֖ךָ וּבִשְׁעָרֶֽיךָ׃ (ס)

(4) Hear, O Israel (alt. God-wrestlers)! The LORD is our God, the LORD alone (alt. is One). (5) You shall love the LORD your God with all your heart and with all your soul and with all your might. (6) Take to heart these instructions with which I charge you this day. (7) Impress them upon your children. Recite them when you stay at home and when you are away, when you lie down and when you get up. (8) Bind them as a sign on your hand and let them serve as a symbol on your forehead; (9) inscribe them on the doorposts of your house and on your gates.

(יג) וְהָיָ֗ה אִם־שָׁמֹ֤עַ תִּשְׁמְעוּ֙ אֶל־מִצְוֺתַ֔י אֲשֶׁ֧ר אָנֹכִ֛י מְצַוֶּ֥ה אֶתְכֶ֖ם הַיּ֑וֹם לְאַהֲבָ֞ה אֶת־ה' אֱלֹֽהֵיכֶם֙ וּלְעָבְד֔וֹ בְּכָל־לְבַבְכֶ֖ם וּבְכָל־נַפְשְׁכֶֽם׃ (יד) וְנָתַתִּ֧י מְטַֽר־אַרְצְכֶ֛ם בְּעִתּ֖וֹ יוֹרֶ֣ה וּמַלְק֑וֹשׁ וְאָסַפְתָּ֣ דְגָנֶ֔ךָ וְתִֽירֹשְׁךָ֖ וְיִצְהָרֶֽךָ׃ (טו) וְנָתַתִּ֛י עֵ֥שֶׂב בְּשָׂדְךָ֖ לִבְהֶמְתֶּ֑ךָ וְאָכַלְתָּ֖ וְשָׂבָֽעְתָּ׃ (טז) הִשָּֽׁמְר֣וּ לָכֶ֔ם פֶּ֥ן יִפְתֶּ֖ה לְבַבְכֶ֑ם וְסַרְתֶּ֗ם וַעֲבַדְתֶּם֙ אֱלֹקִ֣ים אֲחֵרִ֔ים וְהִשְׁתַּחֲוִיתֶ֖ם לָהֶֽם׃ (יז) וְחָרָ֨ה אַף־ה' בָּכֶ֗ם וְעָצַ֤ר אֶת־הַשָּׁמַ֙יִם֙ וְלֹֽא־יִהְיֶ֣ה מָטָ֔ר וְהָ֣אֲדָמָ֔ה לֹ֥א תִתֵּ֖ן אֶת־יְבוּלָ֑הּ וַאֲבַדְתֶּ֣ם מְהֵרָ֗ה מֵעַל֙ הָאָ֣רֶץ הַטֹּבָ֔ה אֲשֶׁ֥ר ה' נֹתֵ֥ן לָכֶֽם׃ (יח) וְשַׂמְתֶּם֙ אֶת־דְּבָרַ֣י אֵ֔לֶּה עַל־לְבַבְכֶ֖ם וְעַֽל־נַפְשְׁכֶ֑ם וּקְשַׁרְתֶּ֨ם אֹתָ֤ם לְאוֹת֙ עַל־יֶדְכֶ֔ם וְהָי֥וּ לְטוֹטָפֹ֖ת בֵּ֥ין עֵינֵיכֶֽם׃ (יט) וְלִמַּדְתֶּ֥ם אֹתָ֛ם אֶת־בְּנֵיכֶ֖ם לְדַבֵּ֣ר בָּ֑ם בְּשִׁבְתְּךָ֤ בְּבֵיתֶ֙ךָ֙ וּבְלֶכְתְּךָ֣ בַדֶּ֔רֶךְ וּֽבְשָׁכְבְּךָ֖ וּבְקוּמֶֽךָ׃ (כ) וּכְתַבְתָּ֛ם עַל־מְזוּז֥וֹת בֵּיתֶ֖ךָ וּבִשְׁעָרֶֽיךָ׃ (כא) לְמַ֨עַן יִרְבּ֤וּ יְמֵיכֶם֙ וִימֵ֣י בְנֵיכֶ֔ם עַ֚ל הָֽאֲדָמָ֔ה אֲשֶׁ֨ר נִשְׁבַּ֧ע ה' לַאֲבֹתֵיכֶ֖ם לָתֵ֣ת לָהֶ֑ם כִּימֵ֥י הַשָּׁמַ֖יִם עַל־הָאָֽרֶץ׃ (ס)

(13) If, then, you obey the commandments that I enjoin upon you this day, loving the LORD your God and serving Him with all your heart and soul, (14) I will grant the rain for your land in season, the early rain and the late. You shall gather in your new grain and wine and oil— (15) I will also provide grass in the fields for your cattle—and thus you shall eat your fill. (16) Take care not to be lured away to serve other gods and bow to them. (17) For the LORD’s anger will flare up against you, and He will shut up the skies so that there will be no rain and the ground will not yield its produce; and you will soon perish from the good land that the LORD is assigning to you. (18) Therefore impress these My words upon your very heart: bind them as a sign on your hand and let them serve as a symbol on your forehead, (19) and teach them to your children—reciting them when you stay at home and when you are away, when you lie down and when you get up; (20) and inscribe them on the doorposts of your house and on your gates (21) to the end that you and your children may endure, in the land that the LORD swore to your fathers to assign to them, as long as there is a heaven over the earth.

According to the text, what are Jews commanded to do?

What are the words one is supposed to inscribe on one's doorpost?

Why should they be put on the doorposts at all? What might this symbolize?

What message does having these words posted send? What does it mean to lead a Jewish life based on this?

Knowing this, how would you feel about having these words on your doorpost?

(א) בכלבו מה שנהגו לכתוב זה השם יותר משאר שמות מפני ששם זה נוטריקון שומר דירת ישראל...

...the practice to specifically write the name Sha-dai, as opposed to any other Divine name, [on the outside of the mezuzah scroll] is due to the fact that the letters [shin, dalet, and yud] which spell the aforementioned name can be seen as an acronym for Shomer Dirat/Delatot Yisrael (the Guardian of the dwellings/doors of Israel)...

What can the Mezuzah symbolize?

Reminder of Jewish Principles and Identity

Blu Greenberg, Orthodox Jewish Feminst

A Jewish household is created by the people who live in it, by the way they act, the things they do and don't do, the beliefs they hold.

A mezuzah serves two functions: every time you enter or leave, the mezuzah reminds you that you have a covenant with God; second, the mezuzah serves as a symbol to everyone else that this particular dwelling is constituted as a Jewish household, operating by a special set of rules, rituals, and beliefs.

What do you think makes your home, or anyone's home, a "Jewish home?"

What rules, rituals, or beliefs do you hold most dear?

Protection (Physical, Spiritual)

אמר רבא מצוה להניחה בטפח הסמוך לרה"ר מאי טעמא רבנן אמרי כדי שיפגע במזוזה מיד רב חנינא מסורא אומר כי היכי דתינטריה אמר רבי חנינא בוא וראה שלא כמדת הקב"ה מדת בשר ודם מדת בשר ודם מלך יושב מבפנים ועם משמרין אותו מבחוץ מדת הקב"ה אינו כן עבדיו יושבין מבפנים והוא משמרן מבחוץ שנאמר (תהלים קכא, ה) ה' שומרך ה' צלך על יד ימינך
§ Rava says: It is a mitzva to place the mezuza in the handbreadth adjacent to the public domain. The Gemara asks: What is the reason for this? The Rabbis say that it is in order that one encounter the mezuza immediately upon one’s entrance to the house. Rav Ḥanina from Sura says: It is in order that the mezuza protect the entire house, by placing it as far outside as one can. The Gemara adds: Rabbi Ḥanina says: Come and see that the attribute of flesh and blood is not like the attribute of the Holy One, Blessed be He. The attribute of flesh and blood is that a king sits inside his palace, and the people protect him from the outside, whereas with regard to the attribute of the Holy One, Blessed be He, it is not so. Rather, His servants, the Jewish people, sit inside their homes, and He protects them from the outside. As it is stated: “The Lord is your keeper, the Lord is your shade upon your right hand” (Psalms 121:5).

How do you think a mezuzah (representing God) is supposed to serve as protection?

When do you feel safe in your own home and when do you feel more vulnerable? How about outside your home? What helps you feel safe and warm?

What aphorism/intention could you inscribe on your doorpost that would help you feel secure as you enter and leave your home?

(ז) וְלָֽקְחוּ֙ מִן־הַדָּ֔ם וְנָֽתְנ֛וּ עַל־שְׁתֵּ֥י הַמְּזוּזֹ֖ת וְעַל־הַמַּשְׁק֑וֹף עַ֚ל הַבָּ֣תִּ֔ים אֲשֶׁר־יֹאכְל֥וּ אֹת֖וֹ בָּהֶֽם׃...(כג) וְעָבַ֣ר ה' לִנְגֹּ֣ף אֶת־מִצְרַיִם֒ וְרָאָ֤ה אֶת־הַדָּם֙ עַל־הַמַּשְׁק֔וֹף וְעַ֖ל שְׁתֵּ֣י הַמְּזוּזֹ֑ת וּפָסַ֤ח ה' עַל־הַפֶּ֔תַח וְלֹ֤א יִתֵּן֙ הַמַּשְׁחִ֔ית לָבֹ֥א אֶל־בָּתֵּיכֶ֖ם לִנְגֹּֽף׃ (כד) וּשְׁמַרְתֶּ֖ם אֶת־הַדָּבָ֣ר הַזֶּ֑ה לְחָק־לְךָ֥ וּלְבָנֶ֖יךָ עַד־עוֹלָֽם׃

(7) They shall take some of the blood and put it on the two doorposts and the lintel of the houses in which they are to eat it...(23) For when the LORD goes through to smite the Egyptians, He will see the blood on the lintel and the two doorposts, and the LORD will pass over the door and not let the Destroyer enter and smite your home. (24) “You shall observe this as an institution for all time, for you and for your descendants.

(ז) וְלָֽקְחוּ֙ מִן־הַדָּ֔ם וְנָֽתְנ֛וּ עַל־שְׁתֵּ֥י הַמְּזוּזֹ֖ת וְעַל־הַמַּשְׁק֑וֹף עַ֚ל הַבָּ֣תִּ֔ים אֲשֶׁר־יֹאכְל֥וּ אֹת֖וֹ בָּהֶֽם׃
(7) They shall take some of the blood and put it on the two doorposts and the lintel of the houses in which they are to eat it.

The Same Teaching as the one from Menachot 33b...with a twist

אונקלוס בר קלונימוס איגייר שדר קיסר גונדא דרומאי אבתריה משכינהו בקראי איגיור הדר שדר גונדא דרומאי [אחרינא] אבתריה אמר להו לא תימרו ליה ולא מידי כי הוו שקלו ואזלו אמר להו אימא לכו מילתא בעלמא ניפיורא נקט נורא קמי פיפיורא פיפיורא לדוכסא דוכסא להגמונא הגמונא לקומא קומא מי נקט נורא מקמי אינשי אמרי ליה לא אמר להו הקב"ה נקט נורא קמי ישראל דכתיב (שמות יג, כא) וה' הולך לפניהם יומם וגו' איגיור [כולהו] הדר שדר גונדא אחרינא אבתריה אמר להו לא תשתעו מידי בהדיה כי נקטי ליה ואזלי חזא מזוזתא [דמנחא אפתחא] אותיב ידיה עלה ואמר להו מאי האי אמרו ליה אימא לן את אמר להו מנהגו של עולם מלך בשר ודם יושב מבפנים ועבדיו משמרים אותו מבחוץ ואילו הקב"ה עבדיו מבפנים והוא משמרן מבחוץ שנאמר (תהלים קכא, ח) ה' ישמר צאתך ובואך מעתה ועד עולם איגיור תו לא שדר בתריה (בראשית כה, כג) ויאמר ה' לה שני גוים בבטנך אמר רב יהודה אמר רב אל תקרי גוים אלא גיים זה אנטונינוס ורבי שלא פסקו מעל שולחנם לא חזרת ולא קישות ולא צנון לא בימות החמה ולא בימות הגשמים דאמר מר צנון מחתך אוכל חזרת מהפך מאכל קישות מרחיב מעיים

The Gemara mentions other Romans who converted to Judaism. It relates: Onkelos bar Kelonimos converted to Judaism. The Roman emperor sent a troop [gunda] of Roman soldiers after him to seize Onkelos and bring him to the emperor. Onkelos drew them toward him with verses that he cited and learned with them, and they converted... The emperor then sent another troop of soldiers after him, to bring Onkelos, and said to them: Do not converse with him at all. The troops followed this instruction, and took Onkelos with them. While they grabbed him and were walking, Onkelos saw a mezuza that was placed on the doorway. He placed his hand upon it and said to the soldiers: What is this? They said to him: You tell us. Onkelos said to them: The standard practice throughout the world is that a king of flesh and blood sits inside his palace, and his servants stand guard, protecting him outside; but with regard to the Holy One, Blessed be He, His servants, the Jewish people, sit inside their homes and He guards over them outside. As it is stated: “The Lord shall guard your going out and your coming in, from now and forever” (Psalms 121:8). Upon hearing this, those soldiers also converted to Judaism. After that, the emperor sent no more soldiers after him.

(This is a source for touching the mezuzah, not necessarily for kissing, but still!)

Affirmation of Life / Egalitarianism

ונקיש מזוזה לתלמוד תורה לא סלקא דעתך דכתיב (דברים יא, כא) למען ירבו ימיכם גברי בעי חיי נשי לא בעי חיי

The Gemara says: But if so, let us juxtapose mezuza to Torah study and say that women are also exempt from the obligation of a mezuza. The Gemara rejects this suggestion: This could not enter your mind, as it is written with regard to the mitzva of mezuza: “That your days may be multiplied” (Deuteronomy 11:21). Can it be said that men need life but women do not need life? (No, it can't)

Beyond the juxtaposition of the words in the mezuzah as described, what do you think a mezuzah has to do with life? How might having a mezuzah - or what a mezuzah symbolizes - in your home help lengthen or improve your life?

Unity of God (and the World), and Our Own Fragility

(יג) חייב אדם להזהר במזוזה מפני שהיא חובת הכל תמיד וכל זמן שיכנס ויצא יפגע ביחוד השם שמו של הקדוש ב"ה ויזכור אהבתו ויעור משנתו ושגיותיו בהבלי הזמן וידע שאין דבר העומד לעולם ולעולמי עולמים אלא ידיעת צור העולם ומיד הוא חוזר לדעתו והולך בדרכי מישרים

(13) People must be very careful about the mitzvah of mezuzah because it is an obligation on everyone at all times, so that any time they go out or come in, they will brush against the unity of the name of the Holy Blessed One and remember God's love and wake up from their sleep and errors in the of daily life and know that there is nothing that lasts forever except the knowledge of the Rock of Ages. And they will then immediately return to their true knowledge and and walk on the right path.

Dignity in Having a Permanent Home

(ט) בית הכסא ובית המרחץ ובית הטבילה ובית הבורסקי וכיוצא בהם פטורין מן המזוזה לפי שאינן עשויין לדירת כבוד סוכת חג בחג ובית שבספינה פטורין מן המזוזה לפי שאינן עשויין לדירת קבע שתי סוכות של יוצרים זו לפנים מזו החיצונה פטורה מן המזוזה לפי שאינה קבועה החנויות שבשוקים פטורין מפני שאינן קבועים לדירה.

(9) A toilet, a bath house, a mikveh, and a tannery and those like them, are not required to have a mezuzah because they are not used as a dignified dwelling. A sukkah on Sukkot and a house on a boat are exempt from having a mezuzah because they are not used as fixed dwellings. Two booths of potters, one inside the other, the outer one is exempt from the mezuzah because it is not fixed. Stores in the market are exempt because they are not fixed as dwellings.

Value of Compromise and Peace in Our Homes

Rabbi Leah Doberne-Schor, The Mezuzah, Our Reminder to to Bring Peace to Our Homes

Traditionally, a Jewish home is not complete without a mezuzah on its doorpost.

You may have noticed that a mezuzah is often hanging neither vertically or horizontally, but rather is tilted at an angle. The origin of this custom can teach us about an important Jewish value: Shalom bayit, peace in the home.

The custom to hang the mezuzah at an angle began as the result of an almost one thousand year old disagreement. The great Torah scholar Rashi (1040-1105) ruled that the mezuzah should be hung vertically. He did this because in a Sephardic community, such as the one in which he lived, the Torah is held in a vertical position when it is read. On the other hand, Rashi’s grandsons lived in an Ashkenazic milieu.

Because the Torah is laid in a horizontal position for reading in Ashkenazic communities, these grandsons ruled that the mezuzah should be hung horizontally. In the spirit of compromise, the custom became to hang the mezuzah at an angle.

Put another way, at the very moment when we enter our homes, we are reminded of the importance of finding a way to live in peace with one another.

The point isn’t that we’ll always see eye to eye with the folks we live with; rather, it’s that we commit to working through our disagreements with one another.

The very first word on the mezuzah scroll is “Shema,” or listen. We make a commitment to listen to each other and to find a way to live in peace with each other.

Shalom bayit, like so many of our values, is not to be attained all at once. Rather, we make a commitment to work with our loved ones towards this goal each day, with its blessings, each day, with its challenges.

Each day, when we return to our homes, we see our mezuzah, our reminder of peace and compromise, our reminder of the type of home we would like to create, before ever we cross our threshold.

Rabbi Gabe Greenberg, Parshat Eikev – Mezuzah

The mezuzah is private, but the one on your front gate is shown to everyone. There are not many mitzvot like that, which span the private and the public. I think the sages are indicating an important lesson about compromise. Compromise is a necessary reality of life. Neighbors, partners, family members, diplomats, enemies, have occasion to compromise to both get what they need, though not necessarily what they want. And there can be an urge to hide this compromise, to present a unified front to the world. Let’s keep our internal conversations internal, and present to the world a façade of unification, we’re all in agreement. But the mezuzah tells us – no. You can even show compromise, show an imperfect answer, to the world.

The Power of One (You)

כמאן אזלא הא דתניא עיר הנדחת לא היתה ולא עתידה להיות ולמה נכתבה דרוש וקבל שכר כמאן כר' אליעזר דתניא רבי אליעזר אומר כל עיר שיש בה אפילו מזוזה אחת אינה נעשית עיר הנדחת
The Gemara raises a similar question: In accordance with whose opinion is that which is taught in a baraita: There has never been an idolatrous city and there will never be one in the future, as it is virtually impossible to fulfill all the requirements that must be met in order to apply this halakha. And why, then, was the passage relating to an idolatrous city written in the Torah? So that you may expound upon new understandings of the Torah and receive reward for your learning. In accordance with whose opinion is this? It is in accordance with the opinion of Rabbi Eliezer, as it is taught in a baraita that Rabbi Eliezer says: Any city that has even one mezuza or any other sacred scroll cannot become an idolatrous city. It is difficult to imagine an entire city without even one mezuza.

ולמדתם אותם וכו' וכן ושמתם כו' בלשון רבים, אמנם וכתבתם בלשון יחיד...לכן קמ"ל קרא דאם ישראל יחיד כותב מזוזה וקובעה על מזוזת ביתו מציל רבים מדין אדם ומדין שמים, לכן כתוב וכתבתם בלשון יחיד למען ירבו ימיכם, שרבים ינצלו מזה עבור זכות היחיד...

"And you (pl.) shall teach them to your children" etc. and similar "and you shall (pl.) impress these words upon your heart" etc. are in the plural, whereas "And you (singular) shall inscribe them on your doorposts" is in the singular...therefore, the verse teaches us, that if one Jewish person writes a mezuzah and affixes it on the doorposts of her house, she saves many from the decree of man and God. Therefore, it says And you (singular) shall inscribe them on your doorposts" in the singular, "to the end that you (pl.) and your (pl.) children may endure," that many will be saved from this because of the merit of a single person.

Personalizing the Mezuzah

In a Car?

Vanessa L. Ochs, Inventing Jewish Ritual

If it is affixed to your car with a magnet, it's called a car mezuzah...If it is to be carried or hung from the rearview mirror, it is called by the tongue-in-cheek title, "Baruch Ha-Car."...

The Baruch Ha-Car Traveler's Prayer offers spiritual comfort for travelers along life's highways. The cyclindrical capsule of solid brass and clear acrylic contains a traditional prayer for those setting out on journeys...

One day in Colorado, I was given a ride by a rabbi I had been visiting. In his car - affixed to the door on the driver's side by a magnet - I saw my first car mezuzah in use. He explained that he spent a lot of time in his car and tended to be a "lead foot." His wife gave him the car mezuzah to remind him to drive slowly and safely, for his sake and for others...If the presence of this new object prompted the rabbi, over and over again, to "choose life" - a central Jewish concept - was it not serving a valid and sacred ritual role?

On a Necklace?

Vanessa L. Ochs, Inventing Jewish Ritual

A former student, a Jewish soldier in the US marines...always wears a silver mezuzah on a chain around his neck; it is for him a symbol of his commitment to Judaism, one the comes before all his other commitments. The mezuzah he describes as "very holy" is not even a mezuzah according to Jewish law, as it lacks the necessary parchment with God's name written on it. Even if it did have the proper parchment inside, according to Jewish law, it would be meaningless, curious, or even offensive when hung around someone's neck as jewelry, and not placed on a doorpost, where Jewish law says it belongs. For this soldier, however, the "mezuzah" he wears is holy, even if it is but a silver miniature of an empty mezuzah case. He has vowed that he will never take it off, so strong is his belief, and so strong is its pull on him. He says, "I live with it on, and I will die with it on."

Interactive Mezuzah

Vanessa L. Ochs, Inventing Jewish Ritual

...He and Peter explained to the others what a mezuzah was, and why it was an important ritual object for may Jews, even those who do not think of themselves as "religious," as it denotes pride in one's Jewish identity and a wish for divine protection. They explained how the text of the mezuzah emphasizes the centrality of study and teaching. I then invited everyone to write their own blessings for their continuing study of sacred texts - Torah, New Testament, and Koran - that would take place here in this office. They rolled their blessings up into tiny scrolls and placed them into a brown envelope that one student had attached to the wall, just below the mezuzah.

During the year, as their studies progressed, they could, I explained, add new blessings to the envelope. I called it an "interactive mezuzah," or in Hebrew a mezuzah nosefet, an additional mezuzah...Unlike the traditional mezuzah...the "interactive mezuzah" holds the words of one's own heart. It is not an alternative to the traditional mezuzah, but an elaboration and extension of its powers and purposes.

Make Your Own Mezuzah Scroll

בָּרוּךְ אַתָּה ה' אֱלֹקֵינוּ מֶלֶךְ הָעוֹלָם, אֲשֶׁר קִדְּשַׁנוּ בְּמִצְו‌ֹתָיו וְצִוָּנוּ לִקְבּוֹעַ מְזוּזָה.

Baruch ata Adonai Eloheinu Melech Ha'Olam, Asher Kidshanu B'mitzvotav Leekbo'ah Mezuza

Blessing for Putting up the Mezuzah

Blessed are You, Lord our God, King of the Universe, Who sanctified us with the commandments, and commanded us to affix a mezuzah.

(א) ובכל עת שיצא מן הפתח יניח ידו על המזוזה ויאמר ה' שומרי ה' צלי על יד ימיני ה' ישמור צאתי ובואי מעתה ועד עולם וענין הנחת יד שכתב מוזכר בהדיא בפ"ק דע"ז (יא.):

Whenever a person walks out from their door, he should put his hand on the mezuzah and say "Hashem is my keeper Hashem is my protector by my right hand. Hashem will preserve my going out and my coming in from now until eternity."

The basis for placing the hand on the mezuzah is mentioned in the first chapter of Avodah Zarah (11a)

ארטבון שלח לר' הקדוש חד מרגלי טבא אטימיטון א"ל שלח לי מילה דטבא דכוותה שלח ליה חד מזוזה א"ל מה אנא שלחי לך מילה דלית לה טימי ואת שלחת לי מילה דטבא חד פולר א"ל חפציך וחפצי לא ישווה בה ולא עוד אלא דאת שלחית לי מילה דאנא מנטיר לה ואנא שלחי' לך מילה דאת דמך לך והיא מנטרא לך דכתיב (משלי ו׳:כ״ב) בהתהלכך תנחה אותך וגו'.

5. The Parthian King Artaban sent to Rabbi Judah a priceless pearl and he said to him: "Send to me something of a value like the value of this". Rabbi sent him a mezuzah.

He sent to him: "I sent to you an item of great value and you sent me an item whose value is one tenth of it!" The rabbi replied: "My goods and your goods cannot equal her". And further you sent me something that it is necessary for me to protect, but I sent you something which is full of knowledge and will protect you, as it is said: "When you walk it will lead you; When you lie down it will watch over you; And when you are awake it will talk with you (Proverbs 6:22)"

ברכי יוסף י"ד רפה:ד

יניח ידו על המזוזה וכו': והאריזצ"ל כתב יניח אצבע הנקרא "אמה" על שד"י וינשקנו ויתפלל לה' שישמרנו

Birkei Yosef on Yoreh Deah 285:4

You should place your hand on the mezuzah:The Arizal (the founder of contemporay Kabbalah) wrote that you should put your index finger on the name of God on the mezuzah and he should kiss his finger, and should pray that God will protect him.