A case is presented by Rav Chiya bar Avin in today’s daf (Nedarim 34b) about someone who makes a vow, saying: “my loaf of bread is forbidden [as if it would have been consecrated to the Temple] to you (i.e. a specific person which that individual identifies)” and then gives the loaf of bread to the person that they identified. The question, as discussed in the Gemara, is whether the vow was predicated on the first person’s ownership (i.e. “my loaf”) – such that once the loaf was given to the second person, the vow is no longer valid? Or, alternatively, do we rule that the vow relates to the loaf in terms of its usage by the receiver such that, even though he or she now possesses the loaf, they cannot benefit from it? The answer given by the Gemara is that, “even though [the vower] gave [the loaf] as a gift, it remains prohibited [to the receiver]”.
You may wonder how this law applies to us today? In fact, the Maharsham (Rabbi Shalom Mordechai Schwadron, 1835-1911) quotes it in his commentary while discussing the laws of eating bread and offering hospitality.
We are taught in the Shulchan Aruch (Orach Chaim 170:19) that, ‘guests who come to someone else’s home are not permitted to wash and take bread, or to give their children or to the servant of the host, without first asking permission from the host’. As the Mishna Berura explains (which referencing a truly tragic story recorded in Chullin 94a), this is because we never truly know the economic status of a person or family, and by presuming that just because you have been invited into someone’s home that you can automatically take food – or more specifically in the case of Chullin 94a, as much food as you like – you may, in fact, be the cause of great stress by taking food that was not for you.
With this in mind, the Maharsham references our Gemara in his discussion of the above mentioned halacha of the Shulchan Aruch where he addresses the interesting question of at what point, if ever, does the food that you offer others to eat in your home become theirs, or does it always remain the possession of the hosts? And why is this relevant? Because beyond the courtesy of asking a host for permission to eat, as our Gemara comes to teach us, it is possible that some of the food owned by the host may not, in fact, be eaten.
Overall, while there are various technical lessons that we learn from today’s daf about vows, there is a practical lesson, echoed in the Shulchan Aruch, which is worthwhile remembering, which is that if you are in someone else’s home, ask before taking food – unless they have already given you permission to do so.