If any man among you seemeth to be wise in this world, let him become a fool. 3:18
Trivia: According to 1 Corinthians 3:18, how can you become wise?
Paul says that the other apostles traveled with their wives - including Peter. We know from Mark 1:30 that Peter had a wife, since Jesus cured his mother-in-law. Paul confirms Peter's marital status here.