One of the most common errors taught concerning Saul of Tarsus is that he was converted and saved on the road to Damascus. The singular defense of this doctrine is Ananias’ use of the word “brother” (“adelphos”) in addressing Saul in verse 17. Among the commentators so claiming include Adam Clarke, JFB, A.T. Robertson, Vincent, Albert Barnes, Matthew Henry, Schaff, and Wycliffe.
Adelphos appears more than 340 times in the New Testament. Of the numerous commentaries I researched, only the IVP Bible Background Commentary gave the varied usages for the word as it is here translated “brother.” They gave those usages as “coreligionists, fellow members of the same Greek association or fellow Jews.” Of course, the word also is used to speak of physical brothers, but it can also include women as fellow Jews (cf Acts 1:15-16; 2:29).
One of the biggest problems with the idea that Ananias recognized Saul as a brother in Christ is Ananias’ own statement to Saul recorded by Luke in Acts 22:16. Recounting his conversion, Saul (now Paul) said that Ananias spoke the following words to him after he received his sight, “And now why are you waiting? Arise and be baptized, and wash away your sins, calling on the name of the Lord.”
You see, Ananias recognized that Saul was still in his sins. Therefore he commanded him to be baptized and wash away his sins. A man who is still in his sins cannot rightfully be called a brother in Christ.
The use of the term “brother” is not a title but rather an expression of Saul’s common Jewish heritage. Consider it as akin to the Jews’ request to Peter in Acts 2:37. Being convicted in their hearts of their part in the murder of Jesus, and also being convinced that Jesus was risen from the dead, they inquired of Peter and the apostles, “Brothers, what shall we do?” (ESV, NIV).
Jesus used “brother” repeatedly in the Sermon on the Mount when no one had any concept of Christianity, the system of faith that would supplant Judaism.
A man is not a brother until he obeys the gospel of Jesus Christ, which includes immersion in water in order to receive remission of sins.