The right of possession into which the eldest son is born. The first son born to the father occupied a prominent place in the Hebrew family (Gen. xxvii. 19, xxxv. 23, xli. 51, xlix. 3; II Sam. iii. 2). Such a one is the "first-born" in the proper sense, and is to be distinguished from sons who are "first-born" merely in the sense of being the first child born to one of the several wives that men might have (Ex. xiii. 2, 12, xxii. 28; xxxiv. 19; Num. xviii. 15).
The first-born son took rank before his brothers and sisters (Gen. xxvi. 31, 32; xliii. 33). Usually the father bequeathed to him the greater part of the inheritance, except when a favored wife succeeded in obtaining it for one of her sons (Gen. xxvii.; I Kings xi. 11-13). In early days the will of the father fixed the part of the chief heir, but the law of Deuteronomy demands for him a double portion of all the possessions and forbids favor being shown to a younger son (Deut. xxi. 15-17). After the death of the father the first-born son was the head of the family; he had to provide for the widows of his father and for his unmarried sisters, since they ordinarily did not have any hereditary rights. The later rabbinical law (Ket. 68a) obliges him to give a dowry when one of them was to be married. The old law claims all the first-born sons (in the larger sense, "whatever opens the womb") for Yhwh (Ex. xiii. 2, xxii. 29). Some explain this by ascribing a certain sacredness to the first-born (Benzinger, "Arch." p. 470); others suppose that the elders were obliged to consecrate them as "nazir" (Smend, "A.-T. Religionsgesch." p. 276). But from Ex. xiii. 12, xxii. 29; Ezek. xx. 25, 26, it is evident that they were to be set aside as an offering for the Deity. It is possible that such offerings were brought in the oldest times, but very soon it became customary to offer an animal instead of the child (Gen. xxii.); and the later law obliges the father to redeem the child (Ex. xiii. 13; xxxiv. 20) for five shekels (Num. iii. 47; xviii. 15). See Family; First-Born, Redemption of; Junior Right; Primogeniture.
The Talmud recommends, as a rule of education, that a father should never show any preference for one of his children over the others, and points to the unhappy relations between Joseph and his brothers as illustrating the disastrous consequences that may followif one child is privileged (Shab. 10b). The prerogatives of the first-born, as the real head of the family after the father's death, were, however, so deeply rooted in the domestic life of the Jews that the Rabbis could not attempt to make any changes here. In connection with inheritance the expression "first-born" refers only to the ("the first-born son of the father"), and not to the ("the first-born of the mother"); although the latter had many advantages in ritual matters (compare First-Born) which the former could not claim (Bek. viii. 1; B. B. 126b). The always had the rights of the first-born, whether he were a legitimate or an illegitimate son, and even if he were a Bastard (Yeb. ii. 5; Gem. ib. 23a; Sifre, Deut. 215), although the Roman law, on the contrary, distinguished between legitimate and illegitimate children in connection with the law of inheritance (Köppen, "System des Heutigen Römischen Erbrechts," p. 171). The right of the first-born was also possessed by the child that was preceded by a miscarriage, either of a fully developed but still-born infant or one dying just after birth (Bek. viii. 1; Gem. 46b), whereas a child born under such conditions could not be considered a "mother's first-born" (Bek. l.c.). In order to enjoy the primogeniture, the first-born had to be born naturally; hence, that child was excluded at whose birth artificial means were employed; e.g., the Cæsarean operation (Bek. viii. 2). A son, however, whose father had previously had children by a slave or a non-Jewess, had the full rights of the first-born; for, according to Talmudic law, these children were in no wise related to their father (Bek. viii. 1; compare "Maggid Mishnah" on Maimonides, "Yad," Naḥalot, ii. 12).
In doubtful cases, especially with twins, where the primogeniture was not certain, the three following persons were entitled to determine it; viz., the midwife, the mother, and the father, who, however, were not equally privileged as regards the term of the availability of their testimony. The midwife could testify only immediately after the delivery; the mother, only during the first seven days after the birth; while the father was entitled to do so from the eighth day after the birth—i.e., the day of the circumcision—onward (Ḳid. 74a).
The father's identification of the first-born was most important; for, in case there were no witnesses, only he was the first-born whom the father recognized as such, even should it be contrary to the general presumption () (B. B. 127b; Sifre, Deut. 216). Even if the father merely by an incidental remark indicated that such a one was his first-born, the latter had the primogeniture (B. B. 126b). Any doubt as to priority of birth debarred from rights of primogeniture, the rule ("moneys of doubtful ownership must be divided between the claimants") not being observed here (B. B. 127a). The birthright belonged not only to the first-born, but also to his descendants; so that if A, the first-born of B, died during B's lifetime leaving a daughter, C, this daughter entered upon the full rights of A at B's death (B. B. 117a). A posthumous child, however, is excluded from the primogeniture, although a son so born has a part in the heritage. Thus, if two sons of the same mother or of two wives were born after the father's death, the estate is divided between them in equal shares. If there are five sons besides the posthumous one, the first-born receives as his birthright , 1/6 and for his ordinary share —like the other brothers—5/36, making 11/36 of the property (B. B. 142).
The first-born receives a double share of the real and personal estate (B. B. 122b, below; Sifre, Deut. 217). In the division of the real estate by lots, the first-born has the right to claim as the second share the lot adjoining the first share that fell to him (Ḥoshen Mishpaṭ, 277, 2; 174, 2; compare B. B. 12b). The birthright includes only the property the father had in his possession at his death, and not that added later to the estate, either by inheritance or by the collection of debts (B. B. 124a, b; Tosef., Bek. vi. 15).
(Lampronti, 'Paḥad Yiẓḥaḳ," letter א, p. 25e)
In recent times the question has often been raised as to whether government bonds should be considered as outstanding debts in regard to the birthright. Ezekiel Landau regarded stocks and bonds as ordinary promissory notes, since they were subject to the fluctuations in the market; but compare Isaac Elhanan Spector's responsum in M. Horwitz, "Maṭṭeh Lewi," p. 48, Frankfort-on the Main, 1891. It is also a matter of discussion whether, in case a father left assets and liabilities and also ready money sufficient to cover his debts, these should be paid out of his assets or out of the ready money; in the first case, the eldest son would receive a double share of the ready money; in the second, he would receive none of the assets. Most of the authorities have decided this case against the first-born.
Nor does the first-born receive a double share of any improvements () of the estate if the heirs have contributed to it with their own labor or cost (B. B. 124a). (If the father stipulated before his death that the heritage should remain intact for a certain period, then the "bekor" receives also a double share of the profits that have accrued in the business, because he has been obliged to assist in maintaining it (Lampronti, l.c.). The birthright extends only to the estate of the father, and not to that of the mother or of the brothers or sisters (B. B. viii. 4).
Although the father can not directly deprive his first son of the right of primogeniture, he is at liberty to divide his whole property during his lifetime; thus making the share of the first-born equal to that of the other sons, or passing him over entirely (B. B. viii. 5; Gem. ib. 126b). According to Naḥmanides on Deut. xxi. 16, a father violates a religious law if he does not make provision for his first-born to come into his rights. In accordance with this opinion in countries where the law does not recognize the rights of primogeniture, it is a father's religious duty to make special provision on this point (see Spector, in M. Horwitz, ib.). When the first-born enters upon his inheritance, it is his duty to contribute a double share to the payment of his father's private debts; he may, however, renounce his birth-right, and thus be free of the obligation (B. B. 124a). Compare First-Born, Inheritance.
Bibliography:
Shulḥan 'Aruk, Ḥoshen Mishpaṭ, 277-288;
Kirsch, Der Erstgeborene nach Mosaisch-Talmud. Recht, Frankfort-on-the-Main, 1901;
Maimonides, Yad, Naḥalot, i.-iii.;
Saadia, Sefer ha-Yerushot, ed. Müller, vol. ix. of Œuvres Complètes de Saadia.
("the first-born son of the father"), and not to the 
("the first-born of the mother"); although the latter had many advantages in ritual matters (compare First-Born) which the former could not claim (Bek. viii. 1; B. B. 126b). The 
always had the rights of the first-born, whether he were a legitimate or an illegitimate son, and even if he were a Bastard (Yeb. ii. 5; Gem. ib. 23a; Sifre, Deut. 215), although the Roman law, on the contrary, distinguished between legitimate and illegitimate children in connection with the law of inheritance (Köppen, "System des Heutigen Römischen Erbrechts," p. 171). The right of the first-born was also possessed by the child that was preceded by a miscarriage, either of a fully developed but still-born infant or one dying just after birth (Bek. viii. 1; Gem. 46b), whereas a child born under such conditions could not be considered a "mother's first-born" (Bek. l.c.). In order to enjoy the primogeniture, the first-born had to be born naturally; hence, that child was excluded at whose birth artificial means were employed; e.g., the Cæsarean operation (Bek. viii. 2). A son, however, whose father had previously had children by a slave or a non-Jewess, had the full rights of the first-born; for, according to Talmudic law, these children were in no wise related to their father (Bek. viii. 1; compare "Maggid Mishnah" on Maimonides, "Yad," Naḥalot, ii. 12).
) (B. B. 127b; Sifre, Deut. 216). Even if the father merely by an incidental remark indicated that such a one was his first-born, the latter had the primogeniture (B. B. 126b). Any doubt as to priority of birth debarred from rights of primogeniture, the rule 
("moneys of doubtful ownership must be divided between the claimants") not being observed here (B. B. 127a). The birthright belonged not only to the first-born, but also to his descendants; so that if A, the first-born of B, died during B's lifetime leaving a daughter, C, this daughter entered upon the full rights of A at B's death (B. B. 117a). A posthumous child, however, is excluded from the primogeniture, although a son so born has a part in the heritage. Thus, if two sons of the same mother or of two wives were born after the father's death, the estate is divided between them in equal shares. If there are five sons besides the posthumous one, the first-born receives as his birthright 
, 1/6 and for his ordinary share 
—like the other brothers—5/36, making 11/36 of the property (B. B. 142).
) of the estate if the heirs have contributed to it with their own labor or cost (B. B. 124a). (If the father stipulated before his death that the heritage should remain intact for a certain period, then the "bekor" receives also a double share of the profits that have accrued in the business, because he has been obliged to assist in maintaining it (Lampronti, l.c.). The birthright extends only to the estate of the father, and not to that of the mother or of the brothers or sisters (B. B. viii. 4).
