Heart: The Unregenerate is Foolish

A shrewd man keeps his knowledge to himself, but a foolish heart proclaims its folly.

Foolishness is bound up in the heart of a child, but the rod of discipline drives it far from him.

This is an evil in everything that is done under the sun: There is one fate for everyone. Furthermore, the hearts of men are full of evil and madness while they are alive, and afterward they join the dead.