What does 2 Corinthians 11:17 mean?

Paul is setting his readers up to hear him boast about himself, as his opponents in Corinth were boasting about themselves. This is not actually an instance of arrogance by Paul, but a deliberate tactic to put his critics in their place. Self-promotion was the way of the Greek world, especially in Corinth, when some philosophical opponents competed for the attention of their audiences. But self-glorifying boasting was not the Lord's way, as Paul says here. He is clear that the boasting he is about to do will be as a fool and not as Christ's representative.

Still, when he finally begins to "boast," he will not actually be promoting himself so much as God's strength in his weakness. Critics who sneered at Paul had never endured what he had, nor accomplished as much for the sake of the gospel. The power of God, shown in Paul's ability to endure trials and continue to preach, should make the lying critics of Corinth ashamed.