Shabbat 79 - On What to Write a Mezuzah?
The connection between tefillin and mezuzah is obvious from many perspectives – they contain the same passages from Deuteronomy [Deut. 6:4-9 and 11:13-21 – tefillin also have passages from Exodus]; anthropologically, they are both totems and good luck signs; behaviorally, they were traditionally used and touched multiple times a day. The resolution of this particular issue is that duksustos is determined by mezuzah size, since one should not use it for tefillin, while parchment is determined by this shortest phrase in tefillin, the famous “Shema.” Incidentally, there are other passages in Deuteronomy that begin “Shema Yisrael,” but when you use those two words, everyone refers to Deuteronomy 6, including the Talmud here.
Again we see the difference between recommended and acceptable practice – it is a “halakha l’moshe misinai – a law from Moses on Sinai” (in other words, “so old we don’t know when or why it started”) that tefillin texts should be written on parchment and those in a mezuzah on duksustos, but also that in a pinch each can use the other material. But there is a limit to efficiency – a Torah scroll or tefillin text that has worn out may not be remade into a mezuzah using the unwritten margins of the parchment.
The question we would like to ask again it outside the bounds of Talmudic discussion: why include THESE texts in the tefillin or the mezuzah? In modern times, could one choose their own texts, from the Bible or even from other Jewish writing, to signify their highest values? And is there a risk that such ritual behavior crosses the line into superstition? After all, many rabbinic authorities to this day suggest that if you’re having a run of bad luck, you should check your mezuzah. . .
Rabbi Adam Chalom