Among the peoples of Bible times the word ‘brother’ had a wide meaning. Its obvious and most common meaning was to those who were children of the same parents (Gen 25:21-26; Matt 4:18-21). It was used also of a person who was more distantly related, such as a cousin or an uncle (Gen 14:12-14), a fellow member of the same community or nation (Gen 19:7; Lev 25:45-46; Acts 13:26; Rom 9:3), or one’s fellow human beings in general (Lev 19:17; Matt 7:3). (See also NEIGHBOUR.) Jesus used the expression ‘brother’ to indicate the closeness of the relationship between him and his followers (Matt 12:46-50; cf. Heb 2:11-12). Those who become Christ’s people are therefore brothers to each other (Matt 18:15,21; Acts 9:17,30; 15:3,22; 1 Thess 5:25-27).
This shared brotherhood should help produce good relations between believers. They should be more tolerant of each other (Rom 14:10-15), more forgiving (1 Cor 6:5-8), more concerned (2 Thess 3:15), more self-sacrificing (1 John 3:17) and more loving (Rom 12:10; 1 John 2:9-11). They should realize that to sin against a brother is to sin against Christ (1 Cor 8:11-13), and therefore should make every effort to prevent, or correct, such sin (Matt 18:15-20; Rom 14:19-21).