What did Paul and the Jerusalem leaders agree about their mission fields?
Paul and Barnabas received the right hand of fellowship from James, Peter, and John, agreeing that Paul and Barnabas would go to the Gentiles, while the Jerusalem leaders would go to the Jews, the circumcision. This division recognized Paul's primary apostolic role to the non-Jew.
Les explains that when James, Peter, and John, who seemed to be pillars, perceived the grace given to Paul as the primary apostle, they gave to Paul and Barnabas the right hands of fellowship. They shook on the whole deal, and all agreed that Paul and Barnabas should go to the heathen, that is, the Gentiles or non-Jews, while the Jerusalem leaders would go to the Jew, to the circumcision. Les notes that James was already at the head of the list, Peter had lost his place of primary authority and was not even moderating the meeting, and this James was not even one of the twelve. The Jerusalem leaders could only go to the Jew a few more years, because the Romans would overrun Jerusalem and Israel would cease to be a viable entity, being scattered into every nation. It was practically a lost cause because of Israel's unbelief, which is why Paul had to constantly defend his apostleship.