Answer: 2. Litigation between believers.
Paul’s first letter to the church in Corinth sought to address many moral issues that stemmed from the diversity of God worshippers in the synagogue. Although Corinth was one of Paul’s most successful missionary assignments, the diversity allowed for the factionalism of the church, with different members following their own choice of leaders and trying to establish the dominance of one leader over another.
Two other issues Paul addressed were divorce and celibacy in marriage.