The readers of numerous New Testament writings are referred to as “brothers.” Take, for instance, 1 Corinthians 1:10, Galatians 1:11, Romans 1:13, and 2 Peter 1:10. According to the book of Acts, the apostles and the early church already followed this custom (see, for example, Acts 1:15–16, Acts 2:37, Acts 15:3, Acts 15:23).
Here, “brothers and sisters” is written in some Bible translations to indicate that both men and women are referred to by this broad word. It’s obvious that these individuals are not related to each other. Why then do they address one another as “brothers and sisters”?
Jesus defines who are His brothers and sisters
We learn how Jesus redefines what it means to be a member of a family in the Gospels. He’s told His brothers and mother are looking for him. Jesus responds, “Who are My mother and My brothers? […] Whoever does the will of God, he is My brother and sister and mother,” referring to them as His “real” family members (Mark 3:32–35).
Jesus defines brothers in terms of spiritual ties rather than kinship. This does not negate the significance of natural family members (cf., e.g., 1 Timothy 5:8). However, it does indicate that the spiritual bond is now even more solid.
Christians are all children of one Father
Because they all have a unique bond with God the Father, believers are like brothers and sisters. According to Romans 8:14–16, “For everyone who is guided by the Spirit of God is a son of God.” We shout, “Abba,” because you have received the Spirit of adoption as sons, not the spirit of servitude to return to fear. Dad! Our spirit and the Spirit Himself attest to the fact that we are children of God.
“And we know that for those who love God, for those who are called according to His purpose, all things work together for good,” the same chapter states. In order for Him to be the firstborn among many siblings, He also predestined those whom He foreknew to be conformed to the image of His Son (Romans 8:28-29). The only Son of God is Jesus Christ. However, God accepts everybody into His family, making them all into spiritual siblings.
Brotherly love
As fellow believers in Christ, we have an obligation to look out for one another. Although we should love everyone as ourselves, there is a special place for our spiritual family. “So then, as we have opportunity, let us do good to everyone, and especially to those who are of the household of faith,” as Galatians 6:10 states.
According to John 13:34, Romans 12:10, and Hebrews 13:1, we are called to brotherly love. We are obligated to live in harmony and to be sensitive to one another’s suffering (1 Peter 3:8). We are Christ’s bride, the [one global church] united.
