1 Corinthians 1:25

Because the foolishness of God is wiser than men; and the weakness of God is stronger than men.

'Because' -This way that seems foolish to men (1 Corinthians 1:18), is more effective than any idea than man ever came up with. And what people have viewed as "weak" (i.e.. crucified and humbled Jesus), was able to achieve more than all the efforts of men in the past! Note: Paul isn't saying that foolishness or weakness are found in the character of God.

ANOTHER FLAW SEEN IN HUMAN WISDOM:

'He adds. pertinent example of the false judgements of men in this very connection. He reminds the Corinthian Christians of the world's false estimate of them, and so of the fact that God can achieve great results by means which the world despises.' (Erdman p. 34)

Why were the Corinthians so impressed with the world (and why are we)? Seeing that the very world that they were impressed with, despised and looked down on the Corinthian believers? What are you doing admiring someone who thinks you are scum? How can you say that the world can't be wrong about the gospel message, it's wrong about you! The world says, human wisdom says, that most of you are worthless.