Chapter 3, Mishna 1
We can establish an eruv, whether to join houses in a courtyard (eruv chatzeros) or to relocate our Shabbos boundaries (eruv techumin) with any kind of food except water and salt. And we can used proceeds from maaser sheni, the second tithe, to buy any kind of food in Jerusalem except water and salt. Can we make an eruv with wine for a nazir, one who vowed not to drink wine? Can we make an eruv for a priest in a cemetery, where he is not permitted to enter? Rabbi Yochanan teaches that laws based on general statements like spending maasr sheni on “all” kinds of food don’t really mean “all.” Just because the exceptions are not listed doesn’t mean exceptions don’t exist, and even if some exceptions are listed, that doesn’t mean all of them are. Example: women are not obligated on time-bound positive commandments. But women are obligated to eat matzah on Passover. And there are positive commandments like “be fruitful and multiply” which are not time-bound and nevertheless still do not obligate women. Why are women not obligated to bear children? Why were both oxen and sheep mentioned as specifications after the general principle that we spend maaser sheni on any kind of food? What do we learn from Torah laws given in the form amplification-limitation-amplification? And how does this differ from Torah laws given as generalization-specification-generalization?