One of the Rabbinic ordinances developed by the Sages to protect the sanctity of Shabbat and holidays is the rule forbidding moving objects that are considered muktze – that is, things that a person puts out of his mind and does not intend on using during Shabbat or Yom Tov. This can be done either by a conscious act or decision on the part of the person, or alternatively if the object is not usable for any activities that are permitted on Shabbat.
Apart from this general statement, there are many differences in how muktze is defined. Some of the basic definitions are as follows:
- Raw materials that are in a form that does not allow them to be used on Shabbat
- Utensils whose sole use involves an activity that is forbidden on Shabbat
- Objects that are not used because they are disgusting
- Objects whose value is so great that they are used only for very specific tasks
Other categories of muktze include things that a person actively sets aside so that they are not used on, and nolad – something that could not have been prepared for use before because it was “born” or came into existence only on Shabbat.
It is this case of nolad that Massekhet Beitza opens with – beitza she-nolda be-Yom Tov – an egg that was laid on the holiday and did not exist when Yom Tov began. Is it considered ready for use on the holiday, or will it be considered muktze since it did not exist beforehand?
Beit Shammai and Beit Hillel disagree on this point. Beit Shammai permits the use of the egg on Yom Tov, while Beit Hillel forbids it. The Gemara offers several different explanations for their disagreement, including the following:
Rabba said: We are dealing with a chicken designated for food and we are dealing with an egg that was laid on a Festival that occurs after Shabbat, i.e., on a Sunday. And the relevant issue is not the halakhot of muktze; rather, one may not eat the egg due to the prohibition against preparation from to a Festival.
And in this regard, Rabba holds that any egg laid now was already fully developed yesterday, and merely emerged from the chicken today. Consequently, an egg laid on a Festival that occurred on a Sunday may not be eaten, as it was prepared on, despite the fact that it was prepared naturally, by Heaven, rather than by man.
Thus, Beit Hillel forbids use of the egg because it was prepared on Shabbat for use on Sunday (he also forbids it when Yom Tov falls on another day of the week, lest someone mistakenly permit it on Sunday, as well).
It is not clear when exactly halakha considers an egg to be “completed,” but from a biological perspective, it takes almost exactly 24 hours from the time that the egg is released from the ovary of the chicken to the time that it completes the preparation process and is laid. Thus, Rabba is correct that every egg that is laid has been prepared from the day before.