The combination of material in Acts and 1 and 2 Corinthians provides a more detailed picture of Paul's relationship with the church at Corinth than we have for his relationship with any other church. Acts 18:1-18 describes Paul's first visit to the city and the founding of the church there. Paul arrived at Corinth and went to work making tents to support himself. He met Aquila and Priscilla who were in the same business and stayed with them (see the Appendix below for a brief overview of this section).
As was his custom he began his evangelism in the synagogue. Silas and Timothy arrived with financial support (probably from the church at Philippi) which enabled Paul to go full time in his ministry. As often happened the synagogue divided over the teaching of Jesus as Messiah and Paul was asked to leave. However, he was invited to continue his ministry in the house next door to the synagogue and eventually the leader of the synagogue was won over to Christian faith.
Apparently, next door was too close for the Jews who had rejected Paul's message and Acts 18:9-10 indicates that considerable tension and conflict occurred. Near the end of 18 months the Jewish group tried to bring charges against Paul before the proconsul. Gallio threw the case out of court, but Paul left Corinth shortly thereafter sailing to Ephesus from Cenchrea, the eastern port for Corinth.
We know very little of the size or condition of the church when Paul left. Crispus, who had been the leader of the synagogue when Paul arrived, and his family had become believers. Presumably his leadership in the synagogue signified that Crispus was a stable and respectable Jew. Aquila and Priscilla had apparently become believers under Paul's influence, but they left with Paul and went to Ephesus and eventually returned to their home in Rome.
Titius Justus, who opened his home to Paul, is the only other believer mentioned in the Acts 18 account. He is described as a "god-fearer" in Acts 18:7 (most English versions call him a worshipper of God). This was a technical term describing a Gentile who had begun attending synagogue worship, but, for whatever reasons, chose not to fully convert to Judaism. God-fearers provided considerable numerical and financial support in some synagogues. Acts reveals that the god-fearers were usually a fertile field for evangelism in Paul's ministry.
Acts 18:17 provides a tantalizing conclusion to the story of the Jewish attempt to take Paul to court. After Gallio dismissed the case, verse 17 states that "they all" grabbed Sosthenes, Crispus' successor as leader of the synagogue and began beating him up in Gallio's court. The original Greek text does not identify "they all." Later manuscripts state that they were Jews who were upset that Sosthenes' strategy had failed. However, it is more likely that "they all" were Paul's supporters from the Corinthian church. No one needs enemies when their friends are as violent and ungracious in victory as Paul's friends.
The order and timing of the subsequent events is not completely clear but several identifiable events took place between Paul and the church at Corinth before 1 Corinthians was written. In 1 Corinthians 5:9 Paul states that he had already written the Corinthians a letter about not associating with wicked and immoral people. Scholars usually call this the Previous Letter. The theory that 2 Corinthians 6:14-7:1 was a misplaced piece of that letter was quite popular for some time, but is no longer considered likely.
First Corinthians 1:11 states that people from Chloe's house (perhaps slaves sent for this purpose) had brought Paul news of division in the church. 1 Corinthians 16:17 mentions another group of Corinthians, Stephanas, Fortunatus, and Achaicus, who had come from Corinth to see Paul. Because the visit of Chloe's group is mentioned in the past tense and the Stephanas' group in the present tense it is likely that Stephanas' group had arrived