1 Corinthians 1:12

I am of Paul; they were attached to, and ranged under different men whom they claimed as their leaders, though without their approbation; as if one were better than another, and his followers more holy. This caused divisions among them, which Paul lamented, and endeavored by this epistle to heal.

Apollos; an eloquent preacher, who had visited Achaia and Corinth after the apostle. Acts 18:24-28.

Cephas; the great apostle of the circumcision, whose name the adherents of the Mosaic law would be likely to use.

I of Christ; the men who said this probably affected a peculiar intimacy with Christ, which raised them above the necessity of following any human teacher: for men may be proud not only of having a particular human leader but Christ.