What does Acts 16:5 mean?

When Paul and Barnabas travelled through Galatia in central modern-day Asia Minor to plant churches, they found an effective routine. They first entered synagogues and explained how Jesus of Nazareth fulfilled the Jewish prophecies of the Messiah. The synagogue audiences included Jews as well as God-fearing Gentiles who worshiped the Jewish God but hadn't fully converted to Judaism by being circumcised. People from both groups believed the message and accepted Jesus as their Messiah. Paul and Barnabas stayed long enough to establish churches and anoint elders to lead the congregations in their absence (Acts 14:1–23).

After Paul and Barnabas returned home to Syrian Antioch, Jewish Jesus-followers who still identified as Pharisees arrived. They were horrified to see a mix of Jews and Gentiles living life and eating meals together. They quickly convinced some of the Jews that eating with uncircumcised Gentiles was still a sin. They also threatened the Gentiles, saying they needed to convert to Judaism to worship the Jewish Messiah (Acts 15:1).

Paul pushed back strongly—to the point that he publicly confronted Peter, who was visiting from Jerusalem, when Peter stopped eating with the Gentile Christians (Galatians 2:11–14). There is some question as to the exact order in which these various events occurred. The elders of the church in Antioch sent Paul and Barnabas to Jerusalem to ask for a formal ruling from the leaders there. James and Peter agreed with Paul and Barnabas. They sent Silas and Judas Barsabbas back to Antioch with Saul and Barnabas and a formal letter from the church in Jerusalem. The letter explained that Christians do not have to be circumcised or follow the Mosaic law. But the Gentiles should be reminded to be sexually pure, and they should avoid eating blood and meat sacrificed to idols. These are not requirements for salvation, but so the Jewish Christians will feel more comfortable being in community with them (Acts 15:2–35).

In between Paul and Barnabas' return to Antioch and their departure for Jerusalem, Paul apparently heard this same false teaching had spread in the churches they planted in Galatia. He wrote the letter to the Galatians to reaffirm circumcision is not necessary for salvation; the only reason Pharisees cared about it was because eating with uncircumcised Gentiles would cost their reputation among the non-Christian Jews (Galatians 6:12). Now, he and Silas are in Galatia, presenting the council's letter. Knowing decisively that salvation is through faith, not works, only serves to strengthen the Galatians' convictions, and grow their congregations.