Demai, Chapter Three, Mishnah Six
This fascinating and, I think, relevant mishnah deals with a person whose mother-in-law is suspected of not observing the laws of tithing because she is an am haaretz. Can he eat at her house, and if so, what does he have to do to make sure that he doesnt eat untithed produce? To translate this into something to which we might have an easier time relating, this is the classic case of a child who is religiously observant asking how he can eat at his in-laws home. It is interesting that the mishnah is already aware of such a problem. This perhaps demonstrates that rabbis married women who came from families of ame haaretz (ignoramuses).
Finally, as we shall see, Rabbi Judahs understanding of how a mother-in-law relates to her daughter and son-in-law is also remarkable.
1) One who gives [produce] to his mother-in-law [to prepare it], he must tithe what he gives to her and what he takes back from her, because she is suspected of changing any [food] which has spoiled.
2) Rabbi Judah said: she desires the welfare of her daughter and is ashamed [of serving spoiled food] to her son-in-law.
3) Rabbi Judah agrees [with the other sages] that if one gives his mother-in-law seventh year produce, she is not suspected of changing it and giving her daughter to eat of seventh year produce.
Section one: Just as the innkeeper was suspected of switching the food that she is given, so too is a mother-in-law. Therefore, in order to make sure that she doesnt eat untithed food, he must tithe the produce that he gives to her. And in order to make sure that he doesnt eat untithed food, he must tithe that which he gets back from her. However, whereas the innkeeper switched the food probably to keep the good food for herself, the mother-in-law switches the food so that she can give the good food to her daughter and son-in-law. What a nice mother-in-law!
Section two: Rabbi Judah now provides an explanation as for why a mother-in-law might switch the bad food given to her and feed her daughter and son-in-law with better (but nevertheless untithed) food. She wants only the best for her daughter and she is ashamed lest she serve spoiled food to her son-in-law. In other words, she loves her daughter and wants to look good in front of her son-in-law. Does this sound familiar to anyone?
We should note that Rabbi Judah certainly agrees with the statement in section one. We can see that because he explains it. The Yerushalmi concludes that Rabbi Judah is the author of the statement in section one and that there are other rabbis who disagree with him. They hold that a mother-in-law does not switch the produce that her son-in-law brings to her and therefore, one does not have to tithe the produce that he gets back from her, just that which he gives her.
Section three: Rabbi Judah now agrees to something that was said by the other sages, to whom I just referred. While a mother-in-law, according to Rabbi Judah, does not tithe her produce, she is more cautious about the laws of sabbatical produce. Therefore, if during the sabbatical year he gives her permitted produce for her to make him a meal, he does not have to be concerned that she will switch it with forbidden produce. [When we learn Tractate Sheviit, we will learn what produce is permitted during the sabbatical year and what is forbidden]. According to Rabbi Judah, ame haaretz will not eat sabbatical produce even though they are suspected of eating untithed produce.