What does 1 Corinthians 3:5 mean?Paul is expressing frustration with the Corinthian Christians for their lack of maturity in Christ. The fact that they have divided themselves into factions based on which Christian leader they prefer is selfish and childish. Worse, it just doesn't make any spiritual sense. Whatever the earthly motivations were—charisma, ethnicity, style—all that matters is that such cliques are spiritually inappropriate.
Paul begins to demonstrate a truth that seems obvious to some who reading these words with the benefit of hindsight. We must be careful, however. Any Christian can be as blind as the Corinthians were to the senselessness at the heart of our own immature conflicts and jealousies. We're called on to be self-examining (2 Corinthians 13:5) and diligent (1 Peter 1:10) for that very reason. Just because we're saved and redeemed doesn't mean we're immune to living out a "merely human" attitude (1 Corinthians 3:3).
Now Paul asks, what is Apollos? What is Paul? In chapter 1, Paul used sarcastic questions to show them that he was not Christ. Paul was not crucified for them. They were not baptized into the name of Paul. Why would they focus on anyone but Christ, who cannot be divided (1 Corinthians 1:13)? The intent here is the same—posing questions with their own obvious answers.
Paul describes what he and Apollos truly are. They are merely servants of the Lord, used by God to deliver the gospel the Corinthians believed. They each did the task God gave them. In other words, neither is worth following as compared to Christ. Neither is worth division between fellow believers.