What does 1 Corinthians 3:19 mean?

Paul has urged his readers to become foolish according to limited human wisdom in order to become truly wise according to God's wisdom. Now he writes that you can't hold on to both at the same time. Human wisdom and God's wisdom contradict each other. God knows the wisdom of the world to be folly or foolishness and so should all who trust in Christ.

The issue here is not that human beings are incapable of knowing any truth, or any wisdom, at all. God places reason and evidence in our lives and expects us to use them (Psalm 19:1; Colossians 2:8). The problem with worldly human wisdom is the self-deception Paul mentioned in the previous verse. Those wise according to the world's standards believe themselves to be ultimately wise and enlightened. That includes their arrogant rejection of faith in Christ and His death on the cross for human sin. Nonbelievers can be scholars, thinkers, intellectuals, speakers, and teachers (Romans 1:18–23).

God doesn't care. Paul quotes from Job 5:13 to show that God catches those who are supposedly wise in their craftiness. He knows all their supposedly wise ideas and teachings will not help them to escape a face-to-face meeting with Him in the end.