What does 2 Corinthians 11:13 mean?

Much of 2 Corinthians is a defense of Paul's ministry, against accusations from crooked voices claiming he has been false. This section, however, turns the tables to show the believers in Corinth who the men making such accusations really are. Paul very bluntly calls them false apostles—likely a charge they had made against him. Paul, of course, is the one telling the truth. These other men are claiming to be representatives of Christ when they preach a false version of Christ and a false gospel of Christ. That's why Paul calls them deceitful workmen. They have come to the Corinthians under disguise, pretending to be apostles.

It is not clear from 2 Corinthians exactly who these men were. They may have been part of a group labelled "Judaizers." This was the label given to Jewish religious leaders who attempted to persuade Gentiles that they must also follow the Law in order to be truly saved. This group did not deny Christ's message outright but destroyed the gospel of God's grace through faith in Christ by adding a component of works.

It's possible the false teachers of Corinth were part of another group, entirely. Perhaps they were pretending to be apostles of Jesus in order to make money. Maybe they wanted the Corinthians to mix the worship of Jesus with the worship of idols. Whatever the case, Paul makes clear in the following verses that they were being used as servants of Satan.