Every once in awhile someone writes to our website to ask if it’s okay to wear a necklace with a mezuzah pendant. Well, mezuzot are meant for doorways, but here is a great response from Chabad.org:
The Talmud explains in a number of places that a mezuzah affords protection. However, as you mention, the mitzvah of mezuzah is indeed to affix it to your doorway. Using it for any other purpose is in no way the fulfillment of the mitzvah. That said, there are records of people using mezuzot as amulets since ancient times. In fact, the Mishnah mentions that some had the custom to carry a hollowed-out staff containing a mezuzah for protection.
Let’s explore the protective powers of the mezuzah.
On the outside of the mezuzah scroll, G‑d’s name Shaddai (ש-ד-י) is written. The Kabbalists explain that, in addition to being G‑d’s name, it is also the acronym for שומר דלתות ישראל, “guardian of the doors of Israel,” alluding to the protection that the mezuzah affords. In light of this, there is a lively discussion in post-Talmudic responsa whether protection can be obtained only through a properly placed mezuzah in fulfillment of the mitzvah, or whether it can come from any mezuzah.
Many are of the opinion that there is indeed some measure of protection from the mezuzah itself, even when not affixed to a doorway. Accordingly, the Lubavitcher Rebbe advised certain individuals who were dealing with health issues to carry a mezuzah with them (obviously in addition to having kosher mezuzot properly affixed to all the doorways of the house).
(It should be noted that even when the mezuzah is on the doorway, the protection it affords is not necessarily quantifiable.)
So yes, people have been known to carry mezuzot with them. But is it proper to have the mezuzah hanging around your neck?
Life Hanging in the Balance
Expounding on the verse “And your life will hang in suspense before you . . .,” the Talmud explains that this refers to one who hangs up his tefillin on a peg, which is seen as disrespectful. Would hanging a mezuzah around your neck be equally disrespectful?
Two preeminent halachic decisors of the last century, Rabbi Moshe Feinstein and Rabbi Ovadia Yosef, both explain that the Talmud’s caution against hanging sacred items does not apply to hanging them from one's body. Indeed, in ancient times, the Jewish kings were commanded to constantly have a Torah scroll with them, so they would hang the scrolls from their arms.
On a Practical Level
Wearing a mezuzah necklace presents some challenges. Unless it is covered by two opaque layers, a mezuzah (or any other sacred writing, for that matter) may not be brought into a bathroom or any unclean place, or be present in a room during intimate relations. Practically, this means that if you were to wear a mezuzah necklace, you would need to make sure to take it off anytime you walked into the bathroom or even just walked through an unclean place.
Though wearing a mezuzah necklace is permissible and may afford some protection, it is important not to lose sight of the mitzvah itself. Kosher mezuzot affixed properly throughout your home are much more potent than any necklace.