What profit has a man from all his labor In which he toils under the sun? 
Solomon is about to challenge us to not just consider the small works that we do, but to consider the big, major important efforts. He asks, what do you gain from ALL of the WORK in which you TOIL under the sun! After you have exerted your life’s living in working laboriously, after you have exhausted the capacity of your mind in laboring, what is the value, the advantage, what is satisfactorily finished? What is the PROFIT?