2 Corinthians 11:7-8

Again Paul used irony (meaning the opposite of what he said): "or did I commit a sin in humbling myself." This is almost sarcasm. He had written that apostles have the right to refrain from working for a living and to live off the gifts of their audiences (1 Corinthians 9:6; 1 Corinthians 9:14). Yet he had made tents in Corinth and had refused to accept gifts from the Corinthians (cf. Acts 18:3; 1 Corinthians 9:4-15). This indicated to some in Corinth that he did not believe he was an apostle. The other apostles normally accepted support from the recipients of their ministries, and these false apostles evidently did so consistently.

Paul had expounded God’s truth in Corinth without accepting money from his converts there for doing so. He adopted this policy in Corinth and elsewhere because he did not want to burden the people he was currently ministering to. He also did so because he knew there were people who would accuse him of preaching to receive payment. He accepted financial help from other churches while not ministering to them directly ("robbed them") so he could serve the Corinthians without taxing them.