What does Acts 18:18 mean?
Paul is finishing up his second missionary journey. He has been in Corinth for a year and a half. As usual, he started by teaching about Jesus in the synagogue until enough of the Jewish leadership drove him out. He then moved next door to the home of a Gentile Jesus-follower, taking along the ruler of the synagogue who also put his faith in Christ. When the remaining leadership accused Paul of encouraging the worship of a god the Roman government had not authorized, the proconsul threw the case out, saying it was a matter of religious interpretation, not civil law (Acts 18:1–17).Priscilla and Aquila were evicted from Rome by the emperor Claudius and apparently came to Christ in Corinth after Paul joined their tentmaking business (Acts 18:1–3). Paul will leave them in Ephesus where they will disciple Apollos (Acts 18:24–28). They will also host the church in Ephesus (1 Corinthians 16:19) before returning to Rome (Romans 16:3).
Cenchreae was the eastern port of Corinth. Corinth was in the district of Achaia on a large island-like mass of land connected to the Greek mainland by a narrow isthmus. Cenchreae was on the east side of the isthmus while its counterpart Lechaion was on the west. Instead of taking the treacherous route around Achaia, ships often stopped at Cenchreae and were dragged over land to Lechaion where they could reach Delphi. Cenchreae and Lechaion were named after the sons of Poseidon. Phoebe, who hand-delivered Paul's letter to the Romans, was possibly a deaconess of the church in Cenchreae (Romans 16:1).
It's unclear what kind of vow Paul was under, but probably a Nazirite vow. A Nazirite vow was a tradition from the time of the Mosaic law where Jews would refrain from alcohol, let their hair grow, and dedicate themselves to a period of intense devotion to God (Numbers 6:1–21). Since Paul cut his hair right after he left Corinth, it was probably for his work there. Although the text says he is going to Syria, meaning Syrian Antioch, he lands in Caesarea Maritima on the Judean coast and goes to Jerusalem first. The resolution of a Nazarite vow requires an offering at the temple. "Nazirite" means consecrated, devoted, or untrimmed; it doesn't have anything to do with Nazareth. John the Baptist and Samson were to be Nazirites for their entire lives (Judges 13:5; Luke 1:15).
Paul will return to Corinth at least twice more (2 Corinthians 12:14), either because the location is strategic or because the believers need extra help. Second Timothy 4:20 strongly suggests that after Paul is released from his house-arrest in Rome (Acts 28), he takes a fourth and final journey, stopping in Corinth.
