What does 1 Corinthians 1:15 mean?

Paul expressed in the previous verse that he was glad he did not baptize very many of the Christians in Corinth. He is deeply troubled that they have divided themselves into angry factions based on which well-known Christian teacher they are loyal to. Paul wants no part of that. If he had baptized more of them, his concern is that they might somehow think that his doing so would cause more of them to focus on him instead of on Christ.

He asked sarcastically in verse 13 if they were baptized in his name. Now he says emphatically that, since he baptized so few of them, nobody can wrongly say that they were baptized in his name.

Baptism is an important practice for Christians. When He was leaving earth after the resurrection, Jesus commanded His disciples to, "Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit" (Matthew 28:19). The idea that anyone would be baptized in the name of Paul was ridiculous heresy. That was Paul's point.

Parallel to that, this passage demonstrates that Paul did not consider baptism and salvation to be one and the same. Despite his deep desire to see others saved (Romans 10:1), Paul will explicitly say his mission was not to baptize (1 Corinthians 1:17), but to preach the gospel. While baptism's importance is clear, what's also clear is that the act of baptism does not impart salvation.