1. Not spiritual, but worldly (1-4)
Paul rebuked the Corinthian Christians as unspiritual. They had fallen into divisions and argued based on whose fellowship they belonged to. Mature Christians do not do such things. There must be no quarreling and no jealousy in the body of Christ. When we do these things, we show ourselves to be worldly-not mature servants of Christ.
2. We are only servants (5-9)
The quarreling among the Corinthian Christians was all the more troublesome because they were quarreling over mere servants of Christ! Apollos, Paul, and any other Bible teacher were servants of the Risen Christ, sent to bring the word of God and point the way to Christ and his salvation. They were all part of the body of Christ-the family of God. There was no point in arguing about who their Bible teacher was. The same is true today. There should be no quarrels amongst denominations. We all belong to the body of Christ. We are all God's co-workers; God's field, God's building.
Application: Father, thank you for calling me into the body of Christ. Help me to be useful to your work, as your fellow worker.
One Word: We are God's co-workers