What does 2 Corinthians 11:24 mean?

Paul is describing ways in which he is a "better" servant of Christ than his opponents in Corinth, a group of false apostles. The tone here is that of satire (2 Corinthians 11:21, 23), not a sincere attempt to self-promote. Paul is deliberately mocking the pattern of secular philosophers who would boast about their experiences and knowledge to show superiority to those who challenged them. Paul is twisting the competition around by "boasting" about his own losses and suffering for Christ instead of his victories.

Now he writes that he received the "forty lashes less one" five times from the religious Jews. These 39 lashes would have been administered in the Jewish synagogues as a severe punishment, likely for blasphemy. Jewish religious leaders objected to Paul's gospel: that Christ was the Son of God and that Gentiles could be saved by believing in Him without following the law of Moses. Jesus warned His disciples that they would receive such floggings (Matthew 10:17).

Deuteronomy 25:1–3 stipulated 40 as the maximum number of lashes that could be given. Perhaps Paul himself had lashed Christians in this way while serving as a Pharisee before his conversion. The fact that he continued to preach the gospel to the Jewish people and submit to the lashes in order not to be excluded from the Jewish community shows his commitment to his people (Romans 9:2–4).