Son of the same father and mother (or of either), but principally son of the same father and mother (see Gen. xlii. 3, 4, 5, 13; xliv. 11, 23, 29; II Sam. xiii. 4 et seq.; Judges ix. 3). The brother was expected to give his consent to his sister's marriage (Gen. xxiv. 50-55, xxxiv. 11 et seq.). The Mosaic law declares the marriage of brother and sister, whether the latter be the daughter of the same father or of the same mother, to be incestuous (Lev. xviii. 9, xx. 17); whereas in the patriarchal time, and even later, it was not considered unlawful to marry the daughter of the same father (Gen. xx. 12; II Sam. xiii. 13). To marry the brother's wife was incest (Lev. xviii. 16, xx. 21); but if a brother died childless, then the surviving brother was enjoined to marry the widow, and the first-born son of this marriage bore the dead brother's name and was his legal heir. In case of the refusal of the brother-in-law to marry her, the widow was required to summon him before the city elders and loose his shoe from off his foot, saying: "So shall be done unto that man that will not build up his brother's house" (Deut. xxv. 5-9; see Ḥaliẓah and Levirate).
The nearest relative occasionally took the place of the brother (Ruth iv. 13; v. 3, 4). The brother was the first, as Goel, to redeem the property sold by an impoverished man, and to avenge the murder of a brother (Lev. xxv. 48; Ps. xlix.). It is probably due to this primitive idea of kinship that the name "brother" came to have the following significations:
- (a) A kinsman. Thus, Lot, the nephew of Abraham, and Jacob, the nephew of Laban, are each called "brother" (Gen. xiii. 8, xiv. 14, xxxix. 15). Furthermore, inasmuch as the whole tribe formed in this sense one family, the name "brother" became also the designation for
- (b) A tribesman (Lev. xxi. 10; Deut. xviii. 7; II Sam. xix. 13 ) or one belonging to the same nation (Ex. ii. 11, iv. 18; Num. xxxii. 6; Deut. x. 9, xvii. 20, xxiii. 19, xxiv. 7; Jer. xxxiv. 14).
- (c) Kindred tribesmen, who are also called "brothers" (Num. xx. 14; Deut. ii. 4, 8; xxiii. 7; Amos i.11).
- (d) Friends by concluding a covenant become actual brothers (II Sam. i. 26; Amos i. 9—"berit aḥim" [covenant of brothers]; compare "aḥavah" [brotherhood], Zech. xi. 14); although, according to Prov. xviii. 24, "there is a friend that sticketh closer than a brother."
- (e) The name "brother" has a higher meaning, and implies brotherly sentiment, in such verses as: "Open thine hand wide unto thy brother, to thy poor" (Deut. xv. 11); "Lest by exceeding the number of stripes thy brother should be vilified unto thee" (Deut. xxv. 3, Hebr.); "Fear thy God that thy brother may live with thee" (Lev. xxv. 36). Indeed, proverbial wisdom states as an experience of life among the Jewish people that "a brother is born for adversity" (Prov. xvii. 17); that is to say, mere sight of distress rouses brotherly compassion.
- (f) Finally, the word "brother" means a fellow-man as son of the same God and Father: "At the hand of every man's brother will I require life" (Gen. ix. 5). "Have we not all one father? hath not one God created us? Why do we deal treacherously every man against his brother" (Mal. ii. 10). "Thou shalt not hate thy brother in thine heart" (Lev. xix. 17). The feeling of brotherly union which gave rise to Ps. cxxxiii., "How good and how pleasant it is for brethren to dwell together in unity," prompted also the prayer recited in the Temple every morning: "May He who dwelleth in this house plant brotherliness and love, peace and friendship, amongst you" (Yer. Ber. i. 3c; compare iv. 7d, a similar prayer by R. Johanan). "Years of plenty and prosperity make of the creatures brothers to each other" (Gen. R. lxxxix.; Midrashic explanation of , Gen. xli. 2). In a far higher sense Abraham by his piety and philanthropy "made brothers" of the whole world (Gen. R. xxxix.; see Brotherly Love).
- (g) "Brother" is also used in the sense of "friend" as a form of politeness (Gen. xix. 7), and
- (h) figuratively in the sense of "companion": "He that is slothful in his work is brother to him that is a great waster" (Prov. xviii. 9); "I am a brother to dragons, a companion to owls" (Job xxx. 29).