1) There was quarreling among the Corinthians over which leaders they followed, such as Paul, Apollos, or Cephas.
2) God chose what seems foolish in the world to shame the wise, and the rulers of this age did not understand the hidden wisdom of God, which is why they crucified Jesus.
3) Paul addresses the Corinthians as mere men since some were acting in an unspiritual manner, such as engaging in immorality. He reminds them that they are God's temple and that God's Spirit dwells within them.