One must make an eiruv tavshillin on Erev Yom Tov in order to permit cooking on Friday (Yom Tov) for Shabbat as, normally, one may not prepare on Yom Tov for the next day. One should take a complete loaf of bread (e.g., a challah roll) and a cooked piece of food and recite the text and bracha of the eiruv (page 327 in the new Chabad Siddur). One who is making the eiruv on behalf of the community should have someone else first lift up the foods on behalf of the community and say the text printed in the Siddur (ani mezakeh).
- For the cooked food, one should use a piece of fish, chicken, or even an egg.
- On Friday, the food should be prepared in such a way that it is all edible before Shabbat begins.
- The food and bread which he put aside should be kept separate and not eaten until Shabbat begins.
- It is preferable to use the roll of the eiruv for Lechem Mishnah on Friday night and on Shabbat day and then to eat it on Shabbat day for the third meal. This follows the principle that if an object was used for a mitzvah, it should be used again for another mitzvah.
- One who did not eat the roll or food on Shabbos has still fulfilled the mitzvah of eiruv.
- One who forgot to make an Eiruv on Wednesday may make it on Thursday (the first day of Yom Tov) by first saying, “if today is Yom Tov then tomorrow is not and I don’t need an Eruv. If tomorrow is Yom tov, then I must make an Eiruv, and I am hereby doing so.
- One who forgot to make the eiruv until it was already Thursday night of Friday may be able to rely on the eiruv made by the rabbi of the community as follows: If one completely forgot to make an eiruv or was so busy that he did not have a chance to do it, he may rely on the eiruv that was made by the rabbi of the community on behalf of all the community members.
- Similarly, an unlearned person who did not know about this mitzvah or who thought that one may rely on the rabbi in the first place and thus did not make his own may rely on the rabbi’s eiruv (even though his thinking was wrong). Some say that one may only rely on the rabbi’s eiruv one time in his life.
- However, if one postponed making the eiruv in a manner that is negligent, he cannot rely on the rabbi’s eiruv. Rather, he should give his ingredients to a friend or neighbor who did make an eiruv and have the friend cook for him.
One who will be a guest for both eating and sleeping at someone else’s house need not make his own eiruv tavshilin as he is considered to be a member of his host’s family. Some say that he should make his own eiruv but without a bracha.
One who does not plan on cooking at all on Friday but is planning to light Shabbat candles should make an eiruv without a bracha.
The eiruv only permits one to cook on the second day of Yom Tov (Thursday night or Friday) for Shabbat but not on the first day (Wednesday night or Thursday) for any other day.
