Romans 16 is a chapter fully on the practical church life. This chapter uses the term church or churches five times, and this term is used absolutely not in a doctrinal way. The first time chapter sixteen uses the term church, it is in the way of a local church, the church in Cenchrea. Few other chapters in the Epistles use the terms church or churches so many times.
In addition, no other chapter in the Epistles uses the term sister more than once. The term brother is used often in the New Testament, but the term sister is used less often. Nowhere else do you find the phrase, "our sister." Paul began this chapter by saying, "I commend to you our sister." In the following verses he greeted a number of brothers, but he did not say "our brother." Only in recommending Phoebe did he say "our sister."
There is another unusual concept in this chapter on the practical church life in verse 13, "Greet Rufus, chosen in the Lord, and his mother and mine." The emphasis in Romans 16 is on the sisters, not the brothers, and there is mention of a mother, but no mention of a father. Neither the sister nor the mother is the one in the flesh. "I recommend to you our sister," not a sister in the flesh. The mother is the mother of Rufus in the flesh, but she was also Paul's mother. Surely she was not Paul's mother in the flesh. We do not have a verse to tell us the names of Paul's mother and father in the flesh. The mother in verse 13 is a mother in the flesh in relation to Rufus, but more important, she is a mother not in the flesh in relation to Paul.
The New Testament tells us that Paul had at least two sons, one named Timothy and the second named Titus, but these were not his sons in the flesh. Paul uses a very intimate expression to call them sons, "Timothy, my own son," and "Titus, mine own son" (1 Tim. 1:2; Titus 1:4). However, the New Testament tells us very little about the direct flesh relatives of the apostles. We cannot find a verse to tell us how many sons and daughters Peter had. But Peter did tell us that he had a son named Mark, "My son Mark." Surely Mark was not Peter's son in the flesh. The Bible tells us that Mark's mother was named Mary, but it does not tell us the name of his father in the flesh. Peter was Mark's father, not his father in the flesh but his father in the spirit, his father in the common faith.
Not one word in the Bible is wasted. According to the record in John 19, when the Lord Jesus was in His crucifixion, suffering there, quite close to the end of His crucifixion, He looked at His mother in the flesh. At that time altogether four sisters were standing by the cross, watching how the Lord was being crucified. Mary was there, and her sister, and another two sisters also named Mary. Mary's sister was the mother of James and John, so that James and John were the cousins of Jesus. Near the end of His crucifixion, the Lord Jesus looked at His mother in the flesh, and in a sense it was as if He said to her, "Mother, don't behold Me, but behold your son." At the same time He said to His cousin John, "Behold, your mother" (John 19:25-27). This account is not merely a story, and there is a reason that it is recorded only in the Gospel of John, not in the other three Gospels.
Each of the Gospels has records of certain things in a meaningful way. For example, Luke is a book on salvation, and it gives us a special record of the two thieves who were crucified with the Lord Jesus, one who made a mocking over the Lord, and the other who rebuked the mocker and called on the Lord. The Lord told him that on that day he and the Lord will be in Paradise (Luke 23:39-43). This record in Luke is not merely a story. The Lord's word to the thief on the cross indicates salvation, and Luke is a book on salvation. This record is not in John, for John is not a book on salvation. Luke's record is not in John, and John's record is not repeated in Luke.