Ecclesiastes 1:8

1:8 All this monotony is tiresome; no one can bear to describe it:

The eye is never satisfied with seeing, nor is the ear ever content with hearing.

Ecclesiastes 2:23

2:23 For all day long his work produces pain and frustration,

and even at night his mind cannot relax!

This also is futile!

Ecclesiastes 12:13

12:13 Having heard everything, I have reached this conclusion:

Fear God and keep his commandments,

because this is the whole duty of man.