Beitzah 2:1

By :  Daniel Nevins Former Pearl Resnick Dean of The Rabbinical School and the Division of Religious Leadership Posted On Jan 1, 2008 | Mishnat Hashavua

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!


  1. Jewish festivals are meant to be extra joyous, which is why cooking is permitted. Why didn’t that permission extend to Shabbat?
  2. 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?
  3. Does this loophole enhance our awareness of sacred time or trivialize it?