Shabbat 75: Listening to a Magosh, Storing Things Like Menstrual Blood

The rabbis consider the prohibition against tearing and sewing on Shabbat.  They almost immediately note that anyone who listens to the words of a magosh, a magi or sorcerer who is a a Persian priest might be punished - or, perhaps, they might be punished only if the learning is acted upon.  It was important for members of the Sanhedrin to know about constellations, astronomical seasons and the practices of the magi in case this knowledge should be required in a case.

Regarding trapping deer and breaking the shell of a chilazon for its dye, the rabbis discuss details of these prohibited actions.  Can the shell be broken before or after the chilazon has been killed?  Leaving the chilazon alive longer will allow the dye to become clearer.  Is one liable because one is aware of the law, because one did not intend to to take a life, or because one took a life with or without intention?

The rabbis discuss writing and erasing.  We are prohibited to write two letters on Shabbat.  What if we wrote one large letter even though there is room to write two letters in that place?  What about one who who erases one large letter and in its space there is room to write two?  Usually we are more stringent regarding constructive acts, but the destructive act of erasing is more stringent. 

We learn a new Mishna at the end of today's daf.  It teaches that the rabbis stated an additional principle regarding the halachot of Shabbat: one is liable to bring a sin offering for anything fit to store for future use, typically stored, and carried out into a prohibited domain on Shabbat.  Storing the item demonstrates that the item is significant, even if it is not significant to others.

The Gemara notes that this would exclude the blood of a menstruating woman and the wood of an ashera, a tree designated for idolatry.  It is noted that menstrual blood might be stored to feed to the cat.  The ashera is unfit as it should be destroyed by Torah law.