Siman - Shabbos Daf 78
- Substances that have more than one use
Abaye stated the following rule for determining the shiur of a substance that one is liable for carrying, if that substance has more than one use:
• Any substance that has two uses, one common and one not common, the Rabbonim followed the common use to determine the minimum shiur for liability, even if this results in a leniency. For example, wine’s common use is for drinking, while its use for healing is uncommon. The Rabbonim, therefore, followed its use for drinking, which is a larger measure, even though this results in a leniency.
• Any substance that has two uses, both of which are common, the Rabbonim followed the common use that results in a stringency. For example, honey is used both for eating, as well as for healing. The Rabbonim followed its use for healing, even though it results in a stringency, since a smaller amount of honey is required for healing purposes.
- Minimum shiur for carrying various substances
The next Mishnah continues to identify the minimum shiur for various substances. Included in this list are:
• Paper: Enough to write a tax collector’s receipt.
• Erased paper: Enough to wrap around the mouth of a small flask of b balsam oil.
• Hide: Enough to make a kameya (amulet).
• Parchment: Enough to write the smallest parsha of tefillin, which is “Shema Yisroel”.
- Carrying a tax collector’s receipt
It was taught in a Baraisa that according to the Tanna Kamma, one is only liable for carrying a tax collector’s receipt (קשר מוכסין) if he has not yet shown it to the tax collector. Once he has, it no longer has a use, and therefore one is no longer liable for carrying it. Rebbe Yehuda holds that he is still liable since he has a need for it.
There is a machlokes about what Rebbe Yehuda meant that “he has a need for it”:
• Abaye says that he will retain the receipt, in case the tax collector sends runners after him to check if his taxes were paid. If he could not prove he paid, he would be brought back to the official to be cleared. Rebbe Yehudah holds that he would keep the receipt to avoid this.
• Rava and Rav Ashi bring alternative pshatim.
