What does Acts 16:4 mean?
Visiting churches which Paul had established during his first missionary journey with Barnabas, Paul, Silas, and Timothy are in the province of Galatia in central modern-day Asia Minor (Acts 14:1–23). When Paul and Barnabas had returned home to Syrian Antioch, they discovered Jewish Christians from the sect of the Pharisees vehemently insisting Gentiles needed to be circumcised and follow the Mosaic law—convert to Judaism—before they could worship the Jewish Messiah. Paul and Barnabas disagreed, and the church leaders in Antioch sent Paul and Barnabas to the leaders of the church in Jerusalem for formal guidance. Peter, James—the pastor of the church and half-brother of Jesus—and the other elders agreed with Paul and Barnabas. They wrote a letter and commissioned Silas and Judas Barsabbas to present the letter in Antioch (Acts 15:1–35).After falling out with Barnabas, Paul takes Silas to the churches in the provinces of Syria and Cilicia to pass on the letter (Acts 15:36–41). As they travel north, they meet Timothy in Lystra and bring him along. Paul does circumcise Timothy—not because it is required for salvation, but because Timothy is an uncircumcised Jewish man who is destined to be a leader in the church. Paul knows Timothy will meet less opposition if he is circumcised (Acts 16:1–3).
There are no details here regarding the Pharisaical teachings in Galatia, but Paul's letter to the Galatians proves it is a big problem. Paul starts his letter to the Galatians by reminding them of the gospel which he, as a commissioned apostle to the Gentiles, taught them. He affirms that any additions anyone might make to that gospel are heresy (Galatians 1:6–24). Paul describes how he went to Jerusalem to see Peter, John, and James. They affirmed the gospel Paul was teaching to the Gentiles is accurate (Galatians 2:1–10). Even when Peter and Barnabas temporarily slid back into the legalism of the Pharisees, Paul addressed them publicly (Galatians 2:11–14). Much of the rest of the letter is comprised of strong arguments that salvation is through faith alone, not works like circumcision. Paul finishes by revealing the real motive of the Pharisaical Christians. They know circumcision isn't necessary for salvation, and they know that no one can follow the Mosaic law. But if they are seen eating with Gentiles who have not converted to Judaism, they will lose their treasured reputation among the non-Christian Jews. It's all about image, not Jesus (Galatians 6:12–13).
James understands this. He couldn't care less about the reputations of the Pharisaical Christians (James 2:1–7), but as a pastor he knows the importance of unity in a church gathering.
Silas then joins Paul to deliver the letter to the churches Paul and Barnabas had planted in other regions. There is some confusion about the timing of the visit described in Acts 16, Paul's letter to the Galatians, and the Jerusalem Council in Acts 15. Most likely, Paul wrote Galatians after he had encountered the Pharisees in Antioch but before he and Barnabas left for Jerusalem. As much as the churches in Galatia might have trusted and been relieved by Paul's letter, Silas and the letter from the elders in Jerusalem do much to build their faith (Acts 16:5).