Paul gives the Corinthians a loving but direct diagnosis: their arguing and division is a sign they haven't grown up yet. They're still on a spiritual milk diet when they should be eating solid food. He wants them to see their leaders — Paul, Apollos, whoever — not as rivals but as teammates on the same construction crew. God is the one building something, Christ is the only foundation worth building on, and everyone needs to be careful about the quality of what they're contributing to that building.
