YISRAEL-MEIR LAU

YISRAEL-MEIR LAU
THE PRACTICE OF JUDAISM IN THE LIGHT OF THE ORAL TORAH. Eiruv tavshilin
From Saturday, it is impossible to prepare anything for weekdays and even for a holiday that comes directly on the day following Saturday. Not only that, but also the preparation of anything from the holiday to the Sabbath is prohibited. However, it happens that the holiday falls on a Friday (for example, the 7th day of Pesach), or even on Thursday and Friday in a row (Rosh Hashanah or two days of the holiday that are observed outside the Land of Israel). On the holiday itself, you can cook food, but you can’t cook anything on the holiday on the following Saturday. However, it is not for nothing that the Torah is called Torat Chaim, the Torah of Life. The sages made sure that we could enjoy the dishes prepared on the holiday on the Saturday following the holiday. To do this, the sages established eyruv tavshilin (“combination of cooking”). This ceremony is performed as follows: on the eve of the holiday, in the evening, they take a loaf of bread, challah or a whole matzah with some food that is valuable in our eyes, for example, a piece of meat, fish, a fried or boiled egg, put it aside and say: “Blessed are You, Lord, our God, King of the Universe, who sanctified us with His commandments and commanded us eyruv!” Then they add: “Through this, let it be allowed to bake, boil, cover food, light candles, cook and do everything necessary for the Sabbath on the holiday preceding it, to us and to all the children of Israel living in this city.”
Eiruv tavshilin unites the holiday and Saturday - they seem to become one day. It is customary to eat this food during the third Sabbath meal, using this bread as a lochem mishneh. http://www.jewish-life.com/practice_41.php