The opening lines of Galatians are perhaps the most significant of all of Paul’s letters. By comparing this introduction to the other letters of Paul, Bible students have usually focused on the absence of praise for the Galatian churches. This is certainly true, but something else is missing from the introduction of this letter. Paul normally includes others in the address of a letter (1 Thess 1:1, 1 Cor 1:1). In this case Paul alone is writer of the letter. Barnabas, the logical person to include, is missing. Where is Barnabas?
Richard Bauckham wrote a short article on Barnabas in Galatians in which he suggests that Paul purposely did not include Barnabas because at the time of the writing of the letter, he was still estranged from Paul. When Paul and Barnabas returned to Antioch after planting several churches in Galatia, two things happened. First, men from (allegedly) from James came to Antioch and complained about table fellowship. Peter and Barnabas withdrew from eating with Gentiles, resulting in a stern condemnation from Paul (Gal 2:11-14). Second, Paul hears a report that Gentiles in his Galatia churches are also being pressured to keep the Law, including circumcision. (These events could be reversed chronologically, it does not matter for the point of this argument.)
While it appears that Barnabas and Paul reconcile before Acts 15, it may be that the rift goes deeper than either Galatians or Acts lets on. By the end of Acts 15, immediately after the Jerusalem conference, Barnabas and Paul part company again. The reason Luke gives is the presence of John Mark in a renewed mission to Gentiles. While Bauckham does not say this, I think that the presence of John Mark indicates that Barnabas is unwilling to do Gentile ministry in the same way Paul does. The Incident at Cyprus (Acts 13:4-12) is the key. John Mark leaves after Paul’s dramatic condemnation of unbelieving Jews. In my view, John Mark is reacting to Paul’s ministry to Gentiles who are not God-Fearing Gentiles within the context of a synagogue. In addition, he may have disagreed with Paul over a gospel which did not require Gentiles to at least become God-Fearers, let alone not keep food laws or Sabbaths.
In addition, it is likely that Barnabas was the leader of the first mission effort to Cyprus and Asia Minor. Remember that at Lystra he was thought to be Zeus, implying he was older and “in charge” while Paul was Hermes, the spokesman for Zeus. Paul’s actions on Cyprus and his sermon in Acts 13 make it clear that his theology was going beyond Gentiles in the Synagogue. By taking John Mark back as a travel companion, Barnabas may be signaling his unwillingness to minister outside of the synagogue in quite the way Paul does in Acts 16 and following (balancing synagogue with marketplace ministry, engaging pagan philosophers, etc.)
Admittedly this is speculative, but Bauckham’s reconstruction (and my slight extension of it) seems to explain the absence of Barnabas from the introduction of the letter. If Paul could say “even Barnabas agrees with me,” he would have since that would have silenced the opponents. However, he cannot say this at the time Galatians was written.
Richard Bauckham, “Barnabas in Galatians,” JSNT 2 (1979): 61-70.