His opponents, who had arrived in Corinth, accused Paul of not being an apostle in the full sense and therefore lacking genuine apostolic authority. They, in turn, considered themselves apostles and boasted of ‘being of Christ,’ perhaps suggesting with this nearly technical phrase that they had known Jesus personally or had connections with the apostles of the Church of Jerusalem. In other words, they saw the apostolate as an exclusive club to which Paul could not belong. Paul responds defensively, despite his humility and discomfort with boasting or talking about himself, because circumstances require it. He does so by reminding them that he founded the church in Corinth and that this living community stands as a testimony to the presence and power of God in his apostolic ministry.