We are all members of God’s family because we all have one Father. Jesus is our elder brother, and we are all members of the same family.
Let me relate a little incident that comes to mind when I think about the family of God. It happened in the days when some of the Scottish Christians up in the Highlands were being severely persecuted by the English army. On her way to a secret meeting of believers, a Scottish lass was arrested by an English policeman, who asked her where she was going. She did not want to lie, but she also did not want to betray her fellow believers, so she lifted her heart to the Lord in prayer and asked Him for an answer. This is how she responded to the policeman: “My elder brother died, and I am on my way to my father’s house to hear the will read.”
That was a good answer. Jesus is the elder brother, God is our Father, and it is our Father’s house.
What is the essential feature of the family? I believe it is a shared life source. God the Father is the life source of us all, and we are together in His family. It is not an institution, not an organization, but a life source that we all share.
What is required of us, as members of God’s family? I suggest that it is mutual acceptance. Jesus calls us His brothers because God calls us His sons. If God calls our fellow believers His sons, we have to call them our brothers. That is not always easy. You may choose your friends, but you do not choose your family. Even so, we must accept one another.