There is a positive Torah commandment to write the two paragraphs of “Shema Yisrael” and “Ve’Haya Im Shamo’a” on parchment and affix this parchment on the doorpost of one’s home, as the verse states, “And you shall write them on the doorposts of your home and on your gates.”
Those Obligated in the Mitzvah of Mezuzah-Women
All must be careful regarding the Mitzvah of Mezuzah, for everyone is obligated to perform this Mitzvah. Women are also obligated in this Mitzvah just as they are obligated to perform other Mitzvot. This is derived from the juxtaposition of the verses, “And you shall write them on the doorposts of your home and on your gates. In order for your days and the days of your children to be increased etc.” Our Sages expounded (Kiddushin 34a and Yoma 11b) that women likewise require life and are therefore obligated in the Mitzvah of Mezuzah.
Some say that a woman should not affix a Mezuzah on her own. Nevertheless, Maran Rabbeinu Ovadia Yosef zt”l writes (in his Halichot Olam, Volume 8, pages 201 and 216) that this is incorrect and a woman may, in fact, affix a Mezuzah while reciting a blessing, just like a man.
Children Regarding the Mitzvah of Mezuzah
The Rambam (Chapter 5 of Hilchot Tefillin and Mezuzah) writes: “Children are educated to affix a Mezuzah in their houses.” This means that a Mezuzah should be affixed onto a house where children live (such as a dormitory), for although children are exempt from the Mitzvah of Mezuzah, they should nevertheless be educated to fulfill it just as they are educated to fulfill other Mitzvot. A Mezuzah should therefore be affixed to children’s rooms. This is especially true since Mezuzah is unique in that every time one passes it, one is reminded of the oneness of Hashem’s holy name, the love of Hashem, and that nothing remains forever besides for the knowledge and belief in the Master of the Universe. Additionally, the Mezuzah is auspicious in that it protects those living in the house.
When a Mezuzah is affixed in the house, one should not allow a young boy or girl (under the age of Bar/Bat Mitzvah) to affix it, for their affixing does not exempt adults from the Mitzvah of Mezuzah.
The Merit of the Mezuzah
Our Sages taught (Menachot 43b) that anyone who has Tefillin on his head and arm, Tzitzit on his garments, and a Mezuzah on his doorpost is assured not to sin, for one has many reminders of Hashem’s presence. These Mitzvot are the angels which protect one from sinning, as the verse states, “The angel of Hashem camps around those who fear Him and saves them.” In the merit of the Mitzvah of Mezuzah, one’s entire household is protected from harmful entities. It is for this reason that we write the “שדי” name of Hashem on the Mezuzah, for this is an acronym for “שומר דלתות ישראל”-“Protector of the doors of Israel.”
Whom to Purchase a Mezuzah From
The scribe who writes one’s Mezuzah must be completely G-d-fearing. Because the laws of Mezuzah are complex, one should only buy a Mezuzah from a scribe or a salesman who is known to be completely G-d-fearing. The same applies to Tefillin and Sifrei Torah which should only be purchased from an expert scribe who is completely G-d-fearing. It is preferable for a Sephardic Jew to use a Sefer Torah and Mezuzah written in Sephardic handwriting. The law for Tefillin, however, is somewhat different and a Sephardic individual must make certain to don only Sephardic Tefillin, for there are nuances regarding the writing of Ashkenazi Tefillin which invalidate most of them according to the ruling of Maran Ha’Shulchan Aruch.