Ecclesiastes 10:3

10:3 Even when a fool walks along the road he lacks sense,

and shows everyone what a fool he is.

Ecclesiastes 7:17

7:17 Do not be excessively wicked and do not be a fool;

otherwise you might die before your time.

Ecclesiastes 2:19

2:19 Who knows if he will be a wise man or a fool?

Yet he will be master over all the fruit of my labor

for which I worked so wisely on earth!

This also is futile!

Ecclesiastes 10:14

10:14 yet a fool keeps on babbling.

No one knows what will happen;

who can tell him what will happen in the future?