What is the meaning of the words that are written on the back of a Mezuza?
Shua from Baltimore wrote:
I was looking on the back of a Mezuza scroll and saw some words written at the bottom. I was told that these words are written on the bottom of all Mezuzas, but when I asked what the words meant no one could tell me. Can you help me?
The three words at the bottom of the Mezuza on the outer side of the parchment are "Cuzu B'mucsz Cuzu" -- an altered form of the phrase "Hashem Elokeinu Hashem." It is actually a form of Gematria (Numerology) where each letter is "raised" to its next letter. Thus, an Alef becomes a Bet, and a Bet becomes Gimel, etc. Rav Moshe Isserlis quotes the Hagahot Maimoni as the source for this custom. It is "only" a custom -- a Mezuza without these words is still considered valid.
Maimonides mentions a custom that some people practiced: They wrote the names of angels or other holy names on the same side of the parchment as the two paragraphs of the Sh'ma. He writes that these people "...invalidate the Mezuza and make a mockery of the Mitzvah...." The Hagahot Maimoni does quote other Sages who permitted such additions. We generally follow the ruling of Rav Moshe Isserlish who rules in agreement with Maimonides and forbids these other additions.
- Rav Moshe Isserlis, The Shulchan Aruch, Yoreh Deah 288:15.
- Maimonides, Mishne Torah, "The Laws of Mezuza" 5:4.
- Hagahot Maimoni, ibid.