18:1 Corinth was another leading city of Greece (Achaia). Its two harbors made it a center of trade for the Mediterranean area.
18:2 It appears that in AD 41 Emperor Claudius prohibited Jews from gathering together in Rome. Then in AD 49 he expelled them altogether, probably because the earlier measures did not work. Presumably Aquila and Priscilla were expelled at this time. That they had recently arrived from Italy suggests that Paul arrived in Corinth in about AD 50.
18:3 Tentmakers refers to people who worked in leather, possibly related to working in the goat hair cloth that was made in Cilicia, Paul’s home region. Later rabbinic tradition confirmed the importance of teachers having a trade to help support themselves.
18:4 As was his custom, Paul reasoned in the synagogue, attempting to persuade both Jews and Greeks. The Greeks were likely God-fearers he encountered at the synagogue, but possibly outside as well. An inscription has been found in Corinth that attests to a “synagogue of the Hebrews.” The date of the inscription is debated, but it probably postdates Paul.
18:5 When Silas and Timothy finally caught up with Paul in Corinth, he was engaged in what he did best—preaching the word and bearing witness to the Jews that Jesus was the Messiah.
18:6 Shook out his clothes symbolized that Paul was finished giving priority to Jewish evangelism, as if he were shaking the dust from the folds of his garment. He would concentrate on the more fruitful harvest among the Gentiles. Similarly, in 13:46 Paul and Barnabas responded to persistent Jewish rejection of the gospel by saying they were “turning to the Gentiles.”
18:7-8 Paul’s vow in v. 6 did not mean no one from the synagogue had accepted his message, as the conversion of Crispus and his whole household indicates. Also, since Titius Justus (a Gentile) was said to be a worshiper of God, he almost certainly had been a member of the synagogue that was right next door to his home.
18:9-11 Paul had experienced trouble in previous towns, including Philippi, Thessalonica, and Berea. But the Lord assured him that he would have a productive ministry in Corinth, which explains why he stayed for a year and a half.
18:12 The time when Gallio was proconsul of Achaia, of which Corinth was the capital, is a relatively firm date in NT chronology. An inscription found at Delphi says Gallio was installed as proconsul in early AD 51. Paul appeared before him later that year.
18:14-17 Gallio seemed both perceptive (I refuse to be a judge of such things) and negligent (the beating of Sosthenes did not concern him). Keeping order in a multi-ethnic provincial town, heavily involved in trade and travel, was not easy. Gallio preferred the hands-off approach.
18:18 It is not clear that Paul was the one who shaved his head at Cenchreae. It may have been Aquila. The Greek syntax seems to indicate the latter, but it is uncertain. The vow may have been a Nazirite vow. If Paul was the person who made the vow, his going up to Jerusalem to visit “the church” (v. 22) may have included a stop at the temple to complete the vow and make an offering of his hair. Such activity was unusual for Paul, especially outside of Judea (cp. 21:26), but would have been consistent with his Jewish identity.
18:19-20 Paul’s stop at Ephesus must have been very short since he apparently did not encounter Apollos (vv. 24-28) or the misguided teaching that he countered in his later, extended visit to Ephesus (chap. 19).
18:22 We know it was the Jerusalem church that Paul greeted since he went down from there (Jerusalem is at a higher elevation) to Antioch. His arrival back in Antioch marks the completion of his second missionary journey.
18:23 This marks the beginning of Paul’s third missionary journey. Like the first two, this one began from Antioch and retraced his steps through Asia Minor, particularly the Phrygian region of the province of Galatia.
18:24-25 Apollos was from Alexandria, Egypt, the most learned city in the Greco-Roman world. Since Apollos had been instructed in the way of the Lord, we know that Christianity had reached Egypt by this time. However, his knowledge of Christianity was deficient since he knew only the baptism of John the Baptist. Nonetheless, some take fervent in spirit to mean that Apollos was already filled with the Holy Spirit. However, it is more likely that Apollos was serious about his dawning faith in Christ but had not yet received the baptism of the Holy Spirit.
18:26 We see here that speaking boldly about Jesus is not enough. One must also accurately understand the faith. Priscilla and Aquila served both Apollos and the kingdom by taking time to instruct him.
18:27-28 Once Apollos’s rhetorical skills were coupled with accurate understanding of the Christian faith, he left Ephesus and went to Achaia (Corinth, 19:1). He vigorously refuted the Jews using apologetic and instructional techniques similar to Paul’s. None of this would have been possible if not for the faithfulness of Priscilla and Aquila.