As discussed in a previous edition of Daily Halacha, if a person forgot to make an Erub Tabshilin before Yom Tob, or is unable to do so due to circumstances beyond his control, he may rely on the Rabbi’s Erub and prepare on Yom Tob for Shabbat. When the Rabbi prepares his own Erub Tabshilin, he has in mind not only himself and his family, but also the entire congregation. As such, those who were unable or forgot to make an Erub Tabshilin can rely on the Rabbi’s Erub.
However, in order for this arrangement to work, every congregant must own a share in the Rabbi’s Erub. A person must own his Erub Tabshilin in order for it to allow him to cook on Yom Tob in preparation for Shabbat, and thus if the congregants do not own a portion of the Rabbi’s Erub, his intention to include them is entirely meaningless, as they cannot rely on somebody else’s Erub. Therefore, after the Rabbi prepares his Erub Tabshilin, he must bring it to somebody, like a neighbor, and have him make an act of acquisition on behalf of all the congregants. This procedure is based on a principle known as "Mezakeh Al Yedeh Aher," which says that a person can legally acquire something without even knowing it, if somebody else makes an act of acquisition on his behalf. For example, if somebody wants to give Reuben a gift, but Reuben is not present, he can bring the gift to Shimon and ask Shimon to lift the object with the intention that Reuben should acquire it through this act. Once Shimon lifts the gift with this intention, it comes under Reuben’s legal ownership. Similarly, the Rabbi’s neighbor lifts the Erub with the intention of making an acquisition on behalf of all the congregants. Once he does so, all the congregants acquire a share in the Erub, and may rely on it if they forgot to make an Erub or are unable to do so.
Although the Erub Tabshilin must be at least the volume of a Ke’besah, and if 300 congregation members receive a portion they are obviously receiving much less than a Ke’besah, this system is nevertheless effective. As long as they legally own a share in the Rabbi’s Erub, they are covered if they forget or are unable to make their own Erub.
The Rabbi should preferably perform this procedure with somebody who is not part of his family. If, however, this is not possible, he may have his wife lift the Erub on behalf of the congregation. This is the ruling of Hacham Bension Abba Shaul (Israel, 1923-1998).
Incidentally, the concept of "Mezakeh Al Yedeh Aher" also has important implications regarding gifts on Shabbat. The Sages enacted a prohibition against giving gifts on Shabbat, as they feared that if gifts were allowed people might begin making commercial transactions. This poses a problem when the Rabbi wants to give a book as a gift from the congregation to a Bar Mitzva boy on Shabbat, or if, for example, one wants to give his wife a present for her birthday on Shabbat. The way to avoid this problem is through "Mezakeh Al Yedeh Aher." The one who wishes to give a gift on Shabbat brings it to somebody else before Shabbat, and asks that person to lift the gift with the intention of acquiring it on behalf of the intended recipient. Once he does so, the gift becomes the legal property of the recipient, and it may then be handed to him or her on Shabbat.
Underlying the notion of "Mezakeh Al Yedeh Aher" is the principle of "Zachin Le’adam She’lo Be’fanav," which means that one can perform a legal act on someone’s behalf without his knowledge, as long as this act is beneficial for him. Since giving a gift – or, in our case, a share in the Erub – is certainly to a person’s benefit, the gift may be legally given to him even without his being aware of it. However, a legal action cannot be performed for somebody without his knowledge if it is not necessarily to his benefit. For example, a person cannot pay Reuben the money owed to him by Shimon, and then ask Shimon to reimburse him. Shimon might have his own plans for how and when he wants to repay the loan, and thus paying the debt without his knowledge is considered "Havin Le’adam She’lo Be’fanav" – performing a legal act that is detrimental for a person without his knowing, and the act is thus ineffective.
One who forgot to make an Erub Tabshilin may rely on the Rabbi’s Erub no more than twice. If it happens a third time that he forgot to make his own Erub, the Rabbis considered him a "Poshe’a" (negligent), and he cannot again rely on his Rabbi’s Erub. Some Halachic authorities rule that this applies only if one forgot on two consecutive holidays – such as on Ereb Rosh Hashanah and then again on Ereb Sukkot. However, Hacham Bension Abba Shaul ruled that this applies even if the two occasions when one forgot were not successive.
Summary: If a person forgot or was unable to make an Erub Tabshilin on Ereb Yom Tob, he may rely on his community Rabbi’s Erub, and thus make preparations on Yom Tob for Shabbat, assuming the Rabbi had somebody legally acquire his Erub on the congregation’s behalf. If this happened more than twice, the person may not rely on the Rabbi’s Erub.
