The repeating theme of Paul's first missionary journey with Barnabas was: the gospel caused controversy (Acts 14:1-7).  But, although religious activists repudiated the teaching that Jesus is God's Messiah, many other Jews and Gentiles welcomed the message and were saved.  As the apostles reported back to the church in Antioch (in Syria), they spent time explaining how it pleased God to extend His grace to everybody who believes (Acts 14:27-28).

It was a big moment for the Christian church.  Should all believers in Jesus become Jews and submit to those religious rules, or can they retain their national and ethnic identity and still be full members of the church?  Paul and Barnabas, and Peter, had all experienced how Gentiles had received the Holy Spirit when they believed the gospel.  But religious legalists, former Pharisees in the church, still found it difficult to believe that salvation is through grace alone; and that good works, or obeying religious rules, cannot contribute to salvation (Acts 15:1; Ephesians 2:8-9).

In one way, the Council meeting in Jerusalem should not have happened.  Misguided Christian activists had travelled from Jerusalem to Antioch. They contradicted Paul's teaching - that the Gentiles could be full followers of Jesus without having to become Jews as well.

The apostles in Jerusalem had agreed that nothing should prevent Gentiles coming to faith in Jesus: they did not need to follow the Jewish law to be saved (Acts 15:12-14).  They sent a letter with their conclusions 'down' to Antioch (Acts 15:24-29).  That letter came as a huge relief to the believers.  They had been unsettled by self-appointed, misguided Christians, who wrongly denied the teaching of Paul and Barnabas that God's grace is for everybody who trusts in Jesus.