||Only edition of this halakhic monograph on the subject of various types of eruvin by R. Benjamin Ze’ev Jakobovitz, rabbi of Mahzike Hadas in Copenhagen. This scholarly work addresses five types of eruv, that is, eruv tavshilin (cooking eruv); eruv hazerot (domain eruv); tehumim (boundary eruv); amirot le-nocri (requesting a non-Jew to do work on Shabbat); and Tikkun Eruv Hazerot (repairing an eruv hazerot). The halakhic sources are reviewed and explained on all these issues in Tikkun Eruvin. At the end is a page of errata.
The term eruv (Eruvin) is applied to various symbolical acts which facilitate the accomplishment of otherwise forbidden acts on the Sabbath and festivals. The literal meaning of eruv is "mixing" and it probably connotes the insertion of the forbidden into the sphere of the permissible. Thus, though it is forbidden (biblically, according to some authorities, rabbinically, according to others) to walk further than 2,000 cubits from one's town on the Sabbath or festivals, one may "mix" the forbidden and permitted areas by establishing an eruv tehumim (boundary eruv). This is accomplished by placing sufficient food for two meals (also called eruv tehumim) less than 2,000 cubits from the town, thus establishing another "residence" from which one can again walk the permissible distance in any direction. This ordinance is evidently ancient since its existence is assumed in tannaitic sources. It is discussed extensively in the Talmud and by later authorities.
A similarly old statute (attributed to Solomon in Er. 2lb) is that of eruv hazerot (domain eruv). While carrying between private and public domains is forbidden on the Sabbath, the rabbis also forbade carrying between two private domains. For example, if several houses opened onto one courtyard, an object could not be removed from one house to another, nor from a house to the courtyard (the latter is considered private property, owned by all the residents, if it is surrounded by a wall at least ten handbreadths high). To facilitate such carrying, a loaf of bread (called eruv hazerot) owned by all the residents is placed in one of the houses, thereby symbolically creating mutual ownership of all the dwellings. The houses and courtyard are thereby "mixed" together into one private domain. The sources indicate that eruv hazerot was already practiced in the time of the Second Temple; the details are elaborated in rabbinic literature from tannaitic times down to the later codes.
To "mix" private and public domains in order that an individual may carry from one to the other or within the latter, an eruv is erected around a given settled district. According to most early authorities, this eruv consists of a minimum of four poles at least ten handbreadths high, connected by other poles from top to top, forming the shape of a gate. The accepted practice among Jewish communities for generations has been to erect such an eruv by connecting poles (of the required height) with iron wires. A minority opinion among the authorities, based on a disagreement of interpretation of a talmudic section holds that the poles must also be no more than ten cubits apart.
No eruv, however, can permit carrying within what rabbinic law considers as falling under the biblical definition of public domain. According to most authorities, such a domain is defined as an area crossed by at least 600,000 people (the number of Jews who fled Egypt) every day, and this definition is accepted in law. Since such public domains exist only in the largest cities, an eruv is effective in most areas. Some consider the minority opinion, which finds a biblically defined public domain in most settlements. While individuals refrain from carrying in such areas, the authorities admit that this practice is not required of everyone by law.
According to rabbinical decree, in order to cook for the Sabbath during a festival immediately preceding it, one must establish an eruv tavshilin (cooking eruv). Before the festival, bread and a cooked food (some feel the former is unnecessary) are put aside for the Sabbath. Since the preparation of food for the Sabbath begins before the festival, it may be continued during the holidays. The preparation of food for the festival and that for the Sabbath are thus "mixed." The food prepared before the holiday is "mixed" with that prepared within the day, and the use of both is permitted. The term eruv tavshilin is applied both to the act of setting aside the food and to the food itself. This practice also evidently dates from an early period, since a controversy is recorded between the schools of Shammai and Hillel regarding one detail: Bet Shammai held that not one but two cooked dishes must be set aside. Eruv tavshilin is made by every householder, although, in principle, one man's eruv (e.g., that of the rabbi) can dispense the whole congregation or city. The making of the eruv is preceded by the standard benediction "Blessed art Thou . . . Who hast sanctified us with Thy commandments and hast commanded us concerning the ordinance of the eruv" followed by an Aramaic sentence to the effect that "by virtue of this eruv it is permitted to bake, to cook, and to kindle light as well as to provide for our necessary wants on this festival day for the succeeding Sabbath; for us and for all the Israelites living in this town." In some congregations it is customary to announce before the evening service of the festival that those who have forgotten to make eruv tavshilin are dispensed by the rabbi's eruv. In the Portuguese rite of Amsterdam the congregation was reminded by the hazzan on the day preceding the eve of the festival of the obligation to make eruv. The rules regarding eruv tavshilin are discussed in the Talmud and the codes.