What was happening in 1 Corinthians 6 with believers taking each other to court?

In 1 Corinthians 6, believers in Corinth were embroiled in disputes with fellow church members and were taking those matters before worldly lawyers and courts instead of resolving them within the local church body, before the pastor, elders, or deacons. Paul challenged them for going to law before the unjust rather than before the saints.

Les teaches that the church at Corinth was made up of born-again people brought out of paganism, yet they were plagued with problems. Those problems are in the book because we have the same problems today. In 1 Corinthians 6, these Corinthians had gotten into a real wrangle with a fellow church member and were going to lawyers and the courts instead of taking the matter to the local church body, the pastor, elders, or deacons. Paul's instruction was not to go to the world's lawyers and courts with such problems, but to keep it within the confines of believers. Les also notes that there can come a point when one may have to go to the world's judicial system, as he dealt with in Romans.

1 Corinthians 6:1

Dare any of you, having a matter against another, go to law before the unjust, and not before the saints?

Where were the Corinthians taking their disputes instead of the church?

The Corinthians were taking their disputes to lawyers and civil courts—before the unjust—instead of bringing them to the local church body, its pastor, or church leadership. Paul corrects this, telling believers not to go to the world's courts but to keep such matters within the confines of believers.