Previously, we have seen that for certain materials which may not be carried on Shabbat, a certain minimal amount is considered insignificant enough that carrying it is not a violation. Today’s page brings a mishnah that includes materials that, carried in even the most minute amounts, constitute a violation of Shabbat. These include pepper (a cure for bad breath), tar (heals headaches), perfume, and metal.
The Gemara, in discussing this mishnah, offers a somewhat tangential beraita (rabbinic source that dates to the time of the Mishnah but was not included in the Mishnah) that discusses donations of metal to the Temple. In that source, we learn that certain minimum amounts of different kinds of metal were required for donation:
In the case of one who vows to donate iron to the Temple but does not specify an amount, some teach: He must donate no less than a cubit by a cubit of iron.
The Gemara asks: For what use is metal that size suited?
Rav Yosef said: For a raven impediment. (The roof of the Temple was covered with iron surfaces with protruding nails to prevent ravens from perching there.) . . .
One who vows to donate copper must donate no less than the value of a ma’a of silver.
Rabbi Eliezer says: One must donate no less than the amount needed to forge a small copper hook.
The Gemara asks: For what Temple use is that suited?
Abaye said: They use it to scrape the wicks from the candelabrum, and clean the lamps with it.
In this beraita, we learn that metals must be donated to the Temple in usable amounts. In the case of iron, that means enough material to create a metal spike studded with nails that could be placed on the roof of the Temple to prevent birds form perching there and, well, making a mess (also described on Arachin 6a). In the case of copper, that means a much smaller amount — enough to make a pick used to scrape the wicks out of the Temple menorah.
We have seen that Shabbat halachah frequently derives from the Temple and its operations. But in this case, the minimal amounts of metals that were useful in the Temple are irrelevant to the prohibition on carrying metal on Shabbat. On Shabbat, even the tiniest bit of metal may not be carried, because even the tiniest bit may have value to the person carrying it.
When it comes to the prohibition of carrying on Shabbat, the theoretical or immediate purpose of the metal is not important. Even a small amount of metal could be valuable enough to save and possibly combine with other metals in the future such that it may not be carried on Shabbat. Perhaps the reason for this is that when it comes to Shabbat, we are immersed in a time where creation and productivity is not allowed. The small piece of metal, with so much potential, could lend itself to disturbing that sacred time.