Not long after the council in Jerusalem Paul and Barnabas split up. Here it appears that the issue that caused their split was John Mark. However, the record in Galatians shows us that there was a much deeper reason for the split: - the doctrine of law VS grace.
Galatians 2:9-13
And when James, Cephas, and John, who seemed to be pillars, perceived the grace that was given unto me, they gave to me and Barnabas the right hands of fellowship; that we should go unto the heathen [Gentiles], and they unto the circumcision.
Only they would that we should remember the poor; the same which I also was forward to do.
But when Peter was come to Antioch, I withstood him to the face, because he was to be blamed.
For before that certain came from James, he did eat with the Gentiles: but when they were come, he withdrew and separated himself, fearing them which were of the circumcision.
And the other Jews dissembled likewise with him; insomuch that Barnabas also was carried away with their dissimulation.
Not long after the council in Jerusalem and before Paul and Barnabas split, Peter came to Antioch. He was eating and enjoying fellowship with the Gentile believers. However, when important Judean believers arrived from James, Peter separated himself from the Gentiles. Obviously, the Jerusalem council which had resulted in public acknowledgment of the doctrine of the grace of God was not practiced in Jerusalem even for a short time after the council. The council had recognized that the Gentile believers did not have to keep the law of Moses, but the Judean believers (including Peter) continued to adhere to the law in practice. This in effect made two classes of believers rather than ONE BODY. The actions of Peter influenced others from Judea to separate themselves from the Gentile believers. EVEN BARNABAS was "carried away with their dissimulation!"
Paul reproved Peter in front of everyone and challenged him to rise up and believe the gospel of the grace of God and the ONE BODY of Christ in practice. Shortly following this record Paul and Barnabas split. It is hard to imagine that Barnabas who had spent so many years working with Paul declaring the gospel of grace among the Gentiles could have been so influenced by the legalistic believers from Jerusalem, but he was. Barnabas leaves and is never mentioned again in the book of Acts. It is also at this time that Peter moves out of Jerusalem. It appears that the confrontation by Paul finally hit home and Peter saw the need to get out of law bound Judea.
The record of God's Word is wonderfully accurate and shows us how human the first century believers really were. Let us in our day and time recognize the example of God's Word and walk in the freedom and grace we have been given in Christ Jesus.
Gladly
Acts