What does 2 Corinthians 10:13 mean?

Opponents in Corinth are challenging Paul's authority as a genuine representative of Christ. They pointed to Paul's lack of an impressive personal attitude. Compared to secular orators, Paul was not as entertaining, dramatic, or engaging. In response, Paul replied in the previous verse that those critics were unwise to participate in competition by comparing themselves to others. Paul refused to even attempt to measure up to the standards of Greek society in this way. His mission was not to win a popularity game, which often included blatant self-promotion.

Paul declares that he and his associates will not boast beyond limits. This means they would not overtly promote themselves in order to win a popularity contest against opponents. Instead, they would only boast about what God had given them to do in their own specific area of influence. That mission was nothing more than to reach the Corinthians with the gospel of Christ. By "boasting," Paul means praising God's power in them and God's power for the Corinthians through them. Paul had used that power to reach the Corinthians with the gospel. That's the only thing that mattered to him and the only thing he would boast about.

This serves as a model for all believers: the powerful truth that God does not call those who serve Him to be "impressive" according to the world's standards. Instead, God empowers Christians to be victorious in the specific areas of influence in which He gives them work. All other comparisons and competitions become a distraction to the work that really matters.