What does Acts 21:20 mean?
Paul and the elders of the church in Jerusalem have very different lives. Paul travels a great deal, sharing Jesus' story to Gentiles in pagan towns who know little or nothing of the Jewish God. The elders live in Jerusalem, trying to teach about Jesus to Jews, including Pharisees who think they know everything about the Jewish God. Paul calls Gentiles from their pagan lives to a new life in Christ. The elders call out Pharisees who want this Jesus but don't want to sacrifice their esteemed place in the community provided by rigid law-keeping.This came to a head after Paul and Barnabas returned from their first missionary journey. Pharisaical Christians from Jerusalem told Gentiles they needed to follow the Mosaic law—by being circumcised and keeping a kosher diet—to properly worship the Jewish Messiah. Paul and Barnabas fiercely disagreed and brought the issue to the elders and apostles in Jerusalem. James, the pastor, disavowed the Pharisees and their message and wrote a letter telling Gentiles to refrain from sexual immorality and eating blood and food sacrificed to idols (Acts 15). Paul willingly shared the letter with the churches he planted.
Years later, while Paul is working around the area of the Aegean Sea, a rumor spreads. This is something of the inverse of the prior error: that Paul is not only failing to ask Gentiles to follow the council's reasonable requests, but he's also telling Jewish Christians they should no longer follow the Mosaic law (Acts 21:21).
When Paul denies the accusations, the church in Jerusalem is relieved. Welcoming Gentiles into the church is one thing; completely abandoning the symbol of Jewish national identity is quite another. God's commands to the nation of Israel don't contradict the gospel of salvation. It would have been difficult for evangelists in Jerusalem to witness to Jewish Pharisees if Paul were travelling the world telling Jewish Christians not to be circumcised.
Their solution is for Paul to help a group of men perform the final rites of their Nazirite vow. Ironically, when Paul does so, Jews from a port city on the Aegean Sea accuse him of bringing a Gentile into the synagogue. They start a riot. Paul is "rescued" when the Roman guards arrest him (Acts 21:22–36).
Acts 21:17–26 is an account of Paul reporting to the "upper management" of the early church. He has spent the last several years along the coastline of the Aegean Sea, establishing the church in Ephesus and building up the congregations in Troas, Macedonia, and Corinth. Now he returns to Jerusalem to give an account of his ministry. James and the elders of the Jerusalem church also have news: a rumor is going around claiming Paul teaches that Jews who worship with Gentiles should entirely forsake the Mosaic law. Ironically, when he cooperates with the elders' recommendation to prove his respect for Old Testament truth, Paul is again falsely accused and arrested.
In Acts 21, Paul returns to Judea from his third missionary journey and promptly gets arrested. He begins by visiting Philip in Caesarea Maritima. Church elders in Jerusalem ask Paul to help men fulfill a Nazirite vow, to dispel rumors he has apostatized his Jewishness. While doing so, Ephesian Jews accuse Paul of bringing one of his Gentile Ephesian companions into the temple. The Roman military tribune keeps the enraged crowd from tearing Paul limb from limb by arresting him.
