When Yom Tov occurs on Friday, it is forbidden to bake or cook in a separate pot for Shabbos, unless you make an eiruv tavshilin on erev Yom Tov.¹ 527:1) After the congregation says Barechu at Maariv, you may no longer make an eiruv, even if it is not yet dark. (Magein Avraham, Derech Hachaim) In an urgent situation, you may make the eiruv until the congregation says the Yom Tov Shemoneh Esrei, according to the ruling of the Taz. (Chayei Adam, Mishnah Berurah 527:4) If you, accepted the holiness of Yom Tov, on your own, some hold that you may still make an eiruv. (see Mishnah Berurah and Sha’ar Hatziyun 527:9) ² 527:13) This is done as follows: Take some cooked or roasted food that is eaten with bread, and take bread with it,³ 527:6) In any event, if you only used a cooked food for your eiruv, it is sufficient. (Shulchan Aruch 527:2) and recite the berachah Asher kideshanu bemitzvosav ["Who has sanctified us with the commandments] vetzivanu al mitzvas eiruv. ["and commanded us concerning the mitzvah of eiruv."] And declare: "By means of this eiruv it will be permissible for us to bake, cook, keep food warm, kindle a light and do anything necessary on Yom Tov for the sake of Shabbos." If you do not understand this language, you should say it in the language you understand.

footnotes: ¹ Even at twilight. (Ramah ² This is preferable, but it also helps if you made it many days before, in which case you should still recite the declaration at the end of this paragraph (without a berachah). (Taz, Magein Avraham ³ You only need to take bread if you wish to bake for Shabbos. (Beis Yosef, Vilna Gaon, Mishnah Berurah

The cooked food⁴ 102:6, Korban Nessanel (Beitzah 2:9), Mishnah Berurah] The Maharsham 528:7 rules that in the event you used salted fish etc., you may rely on the ruling of the Chacham Tzvi 130, Tz’lach and Derech Hachaim who rule that it is sufficient. must be the kind usually eaten with bread, like meat, fish or eggs. But food not usually eaten with bread⁵ 16, Shulchan Aruch 527:4) is not acceptable (for eiruv tavshilin). The required amount of the food is a kazayis,⁶ and of the bread, a kebeitzah.⁷ ⁸ it is also enough, but a kebeitzah is better. (Ramah 527:3) You should take a generous portion in honor of the mitzvah. The bread you use should be a whole⁹ 56) loaf and should be placed [on the table], for lechem mishneh¹⁰ on Shabbos. You should eat it at the third Shabbos meal; since one mitzvah was performed with it, it is appropriate to use it for another mitzvah.

footnotes: ⁴ You may not use foods that are merely salted, such as salted herring. [Shulchan Aruch Harav, Chayei Adam ⁵ For example, cooked grain cereals. (Maseches Beitzah ⁶ See glossary. ⁷ See glossary. ⁸ If you used a kazayis, ⁹ In order to perform the mitzvah in its excellence. (Tanya Rabassi ¹⁰ See glossary.

An eiruv tavshilin is effective in permitting you to prepare all your Shabbos needs on Yom Tov [only when you make the eiruv] early in the day; that is, there must be enough time in the day, that should guests arrive, who had not yet eaten that day, they would have enough time to eat and enjoy the food that was prepared on Yom Tov before the onset of twilight. But if there is not enough time (left in the day) to enjoy the benefit of the labor, the eiruv tavshilin is not effective.¹¹ 527:3 rules that if you were late in your preparations, you may be lenient on the second day of Yom Tov, and if it is urgent, you may be lenient even on the first day of Yom Tov and rely on the ruling of the Rambam and Ritva. Therefore, it is customary, when Yom Tov occurs on Friday, to begin Maariv prayers Friday night earlier than usual, while it is still daytime,¹². so that people will hurry to complete all their work before the congregation recites, Mizmor shir leyom haShabbos. The cooked dishes that you want to keep warm for Shabbos, should be put in the oven to warm while it is still broad daylight, so that before twilight, at least one third of the cooking¹³ See Chapter 72. should be done.

footnotes: ¹¹ Mishnah Berurah ¹² Eliyahu Rabbah, Levush ¹³ Peri Megadim.

You are permitted to bake and to cook by means of an eiruv tavshilin only on Friday. If Yom Tov occurs on Thursday and Friday, you are forbidden to cook or bake anything on Thursday for Shabbos.¹⁴ 527:13. If you did, you may eat it on Shabbos. (Taz, Eliyahu Rabbah, Mishnah Berurah)

footnotes: ¹⁴ Shulchan Aruch

The eiruv must remain in tact until you have prepared all your Shabbos needs.¹⁵ was lost, you may continue and complete the preparation of that food. If the bread (of the eiruv) was lost or eaten, it also does not matter; and you are allowed even to bake for Shabbos. But if the cooked food was lost or eaten, if a kazayis is left it doesn't matter. But if less than a kazayis is left, it is forbidden to cook [for Shabbos,] just as if you had made no *eiruv.*¹⁶ but the cooked component was lost and you are left with the bread alone, Sha’arei Teshuvah 527:13, and Penei Yehoshua’s (Responsum 15) rule that if you are lenient and rely on it, you have not done anything wrong. The Semak also rules that you may rely on the baked component. What should you do if you made no eiruv? If you thought of it after the morning (Yom Tov) meal, and in that community there is no other Jew who made an *eiruv,*¹⁷ 527:2. The Magein Avraham, Darkei Moshe say that if there is another Jew, you must do as prescribed (at the end of this paragraph) and may not cook even one dish etc., but the Mishnah Berurah 527:61 (Acharonim (Reshal etc.) hold that the choice is yours. you are perrmitted to cook only one pot,¹⁸ in the house, but it is not enough for Shabbos, you may bake one more to meet those needs. (Sha’ar Hatziyun 527:89) bake only one loaf of bread, and light one¹⁹ who require an eiruv in order to light the Shabbos candles. Rambam, Bach, Knesses Hagedolah, Birkei Yosef etc. permit the lighting of candles even without an eiruv. Mishnah Berurah 527:55 rules that it is proper to be stringent. candle for Shabbos. If you thought of it before cooking the morning (Yom Tov) meal, you may cook all kinds of foods in a large pot²⁰ and leave some over for Shabbos. If there is someone there who made an eiruv, you should give him as a gift, your flour, meat and all other ingredients. The one who made the eiruv acquires possession of these items by lifting them up,²¹ high. (Shulchan Aruch Harav 527:28) and then he may cook and bake for you, even in your house though you did not make an eiruv.

footnotes: ¹⁵ If you started preparing food (like cutting vegetables to cook) and then, the eiruv ¹⁶ From this it seems that you may not bake, even though the bread was left. If you made a proper eiruv, ¹⁷ Shulchan Aruch ¹⁸ Large enough for all your Shabbos needs. Even if you have challah ¹⁹ This is in accordance with most Rishonim ²⁰ This means each kind may be cooked in a pot large enough to suffice for both Yom Tov and Shabbos. ²¹ One tefach

The head of every household is required to make an eiruv tavshilin for himself. Even a woman who has no husband, if she knows how to make an eiruv tavshilin, is required to make one for herself. It is forbidden to rely on the eiruv made by the rabbi of the city. If, because of unavoidable circumstances, you forgot to make an eiruv tavshilin, or you made one, but it was lost, then if someone in the city makes an eiruv, for everyone in the city, (that is, he gives them a share in the cooked dish and the bread, as is explained in the Shulchan Aruch) you may rely on such an eiruv. But if you forgot out of laziness,²² 527:7 rules that it does not help. But Rambam, Rashba, Ran etc. say it does. Mishnah Berurah 527:26 rules that if your (simchas Yom Tov) rejoicing on Yom Tov, will be impaired, you, may be lenient and rely on this opinion. or if you meant to rely on this eiruv from the start, it is ineffective²³ but does not know how to make one. He should have asked someone to make it for him. Since he did not, he may not rely on someone else’s eiruv. (Radvaz 3:475) If he thought he was allowed to rely on someone else’s eiruv, he may rely on it, unless he is a Torah scholar and should have known better. (Shulchan Aruch Harav 527:14, Magein Avraham) and you must conduct yourself, according to the laws laid down in paragraph 5 above.

footnotes: ²² If you deliberately relied on his eiruv, Shulchan Aruch ²³ This applies also to a person who heard that he is obligated to make an eiruv tavshilin,

If Yom Tov occurs on Thursday and Friday, and on Thursday you remember that you did not make an eiruv tavshilin, you may make it on that day, and recite the berachah.²⁴ (Siddur), Birkei Yosef rule that a berachah should not be recited when making a conditional eiruv, for it is a safeik (doubt) and a berachah is not made when there is a doubt. Afterwards you should say, "If this day is Holy (Yom Tov), then I do not need to make an eiruv. And if today is really a weekday, then by means of this eiruv etc." On Rosh Hashanah, this cannot be done.

footnotes: ²⁴ But the Chacham Tzvi, Lechem Setarim, Rabbi Akiva Eiger Ya’avetz