'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.

I have seen that every [effort in] labor and every skill in work comes from man’s rivalry with his neighbor. This too is vanity (futility, false pride) and chasing after the wind.

Better one handful with restthan two handfuls with effort and a pursuit of the wind.

There was a certain man—without a dependent, having neither a child nor a brother, yet there was no end to all his labor. Indeed, his eyes were not satisfied with riches and he never asked, “For whom do I labor and deprive myself of pleasure?” This too is vanity (a wisp of smoke, self-conceit); yes, it is a painful effort and an unhappy task.

For the dream comes through much effort and the voice of a fool through many words.

When I applied my mind to know wisdom and to see the activities [of mankind] that take place upon the earth—how some men seem to sleep neither day nor night—

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.