Both Corinthian letters were written by Paul 'from the defense'. The believing Corinthians distrusted the apostle, so he had to substantiate his apostleship, as it were (see for example chap. 9:1). This had a lot to do with the factions that existed among them. Because of this they did not get to spiritual growth. In 1 Corinthians 3:1 Paul writes: "And I, brethren, could not speak to you as to men spiritual, but only as to carnal men, yet infants in Christ." He therefore begins chapter 15 again with an explanation of the basics of the gospel. The passage of that chapter even shows that some of them no longer even believed in the resurrection of the dead!
Paul writes the letter together with Sosthenes (ch. 1:1), who was ruler of the synagogue at Corinth (Acts 18:17).
By comparing all kinds of data, it is obvious that Paul wrote this letter in Ephesus, when he dwelt there for "a while" (Acts 19:1 and 22ff), after his first visit to Corinth in Acts 18. :1 ff. In 1 Corinthians 2:3-5; 3:6 and 4:15 he refers to this first visit. Apollos was also known in Corinth (chap. 1:12; 3:4 and 16:12), which means that the letter must have been written after Acts 18:27 and 19:1. With 1 Corinthians 3:6, Paul shows what we also find in Acts: First he was there, then Apollos.
Paul had met Apollos (chap. 4:6) between his first and second visit to Corinth (1 Cor. 16:12). In 1 Corinthians 16:1 the congregations in Galatia are mentioned, which Paul visited (for the second time) after his first visit to Corinth during his third journey (Acts 18:23), after which he arrives in Ephesus (Acts 19 :1; cf. also 1 Cor. 16:8 and 19).
Prisca and Aquila are located at Ephesus (1 Cor. 16:19), which tells us that Paul wrote this letter before the Romans letter; for it appears from Romans 16:3 that this couple was again (see Acts 18:2) in Rome.
Furthermore, we see that Paul had sent Timothy (1 Cor. 4:17 and 16:10), which brings us to the time of Acts 19:22 where he sends Timothy and Erastus to Macedonia, while he himself remains in Asia for a while ("until Pentecost," 1 Cor. 16:8). According to Acts 20:4, Timothy is apparently present in Greece at the time. Also 1 Corinthians 16:5 agrees here with Acts 19:21.
The letter was written around the spring of 57.
The church at Corinth had originated from the synagogue. Acts 18:1 tells us that Paul is coming to Corinth. Verse 4 then states, "And he held conferences in the synagogue every Sabbath, and endeavored to persuade Jews and Greeks." Several Jews came to faith there. In time, Paul was forced to leave the synagogue (vv. 5-8). For a year and a half Paul lived in Corinth (v. 11). All in all, a fairly long period, in which he preached to non-Jews as well as to Jews (descendants of the two-tribe kingdom). Of course, among these non-Jews were Gentiles who did not originally even belong to one of the twelve tribes of Israel. Yet there will also have been Gentiles who descended from one of the ten tribes. For example, when Paul refers to 'our fathers' and then to 'all' in 1 Corinthians 10:1 ff., it is clear that he is referring to the entire nation of Israel.
He describes the addressees as "the church of God at Corinth, to those who are sanctified in Christ Jesus, the called saints, with all who in every way call on the name of our Lord Jesus Christ, theirs and ours" (chap. 1:2).
A. 1:1-9 Introduction.
B. 1:10-4:16 Paul from his ministry rebukes the church and explains things.
C. 4:17 The mission of Timothy.
D. 4:18-21 Paul's visit.
E. 5:1-6:20 The things that came to Paul's ears.
E. 7:1-8:13 Things written to Paul.
B. 9:1-15:58 Paul from his ministry rebukes the congregation and explains things.
D. 16:1-9 Paul's visit.
C. 16:10-18 The mission of Timothy.
A. 16:19-24 Closing.
It is difficult to summarize the contents of this letter in a few words. Broadly speaking, it means that there was great division in the church at Corinth. By disbelief in the resurrection, by not accepting that Paul was an apostle, by following leaders too much, by immoral matters, by abuses at the Lord's Supper, by misuse of the spiritual gifts, etc., etc. selected key text below.
"...be ye all of one accord, and let there be no divisions among you; be firmly united, of one mind, and of one mind" (chap. 1:10).