יום טוב שחל להיות ערב שבת, לא יבשל אדם בתחלה מיום טוב לשבת, אבל מבשל הוא ליום טוב, ואם הותיר – הותיר לשבת, ועושה תבשיל מערב יום טוב וסומך עליו לשבת. בית שמאי אומרים: שני תבשילין, ובית הלל אומרים: תבשיל אחד. ושוין בדג וביצה שעליו שהן שני תבשילין. אכלו או שאבד, לא יבשל עליו בתחלה. ואם שיר ממנו כל שהוא, סומך עליו לשבת.
When a yom tov (festival) falls right before Shabbat, a person may not intentionally cook on yom tov for Shabbat. However, he may cook for yom tov, and if there are leftovers, eat them on Shabbat. And he may cook a dish before yom tov and rely on it for Shabbat [see comments]. The Shammai Institute teaches that this requires two cooked dishes, but the Hillel Institute says one cooked dish [suffices]. And they agree that a cooked fish or an egg is like two cooked dishes. If he ate it or lost it, he should not rely on it to cook more food. But if even a bit of the food was left, he can use it to prepare more food for Shabbat.
Rabbinic law allows cooking food on yom tov [Pesah, Shavu’ot, Rosh Hashanah, and Sukkot], but only for yom tov. What, then, will one eat on the day immediately following Shabbat? This Mishnah describes a rabbinic loophole called the “eruv tavshilin” (which is nearly impossible to translate). An eruvis a legal device that “mixes” different domains so that activities permitted in one domain can be extended to another domain. In this case, the eruv is a dish of cooked food. By cooking some food for Shabbat before yom tov [for example, on Thursday, when Friday is yom tov] and saving that food until Shabbat, any subsequent cooking during yom tov for Shabbat is viewed as just an enhancement of the already prepared meal. It is a stretch, but it remains Jewish practice even today!
- Jewish festivals are meant to be extra joyous, which is why cooking is permitted. Why didn’t that permission extend to Shabbat?
- How do you understand the mechanism of eruv tavshilin? Since it technically turns all Shabbat food into leftovers, does that diminish the honor of Shabbat?
- Does this loophole enhance our awareness of sacred time or trivialize it?