'Effort' in the Bible

What benefit do people get from all the effort which they expend on earth?

I did not restrain myself from getting whatever I wanted; I did not deny myself anything that would bring me pleasure. So all my accomplishments gave me joy; this was my reward for all my effort.

Yet when I reflected on everything I had accomplished and on all the effort that I had expended to accomplish it, I concluded: "All these achievements and possessions are ultimately profitless -- like chasing the wind! There is nothing gained from them on earth."

So I loathed all the fruit of my effort, for which I worked so hard on earth, because I must leave it behind in the hands of my successor.

If an iron axhead is blunt and a workman does not sharpen its edge, he must exert a great deal of effort; so wisdom has the advantage of giving success.