Ecclesiastes 3:9-12

What profit hath he that worketh in that wherein he laboureth? I have seen the travail, which God hath given to the sons of men to be exercised in it. He hath made every thing beautiful in his time: also he hath set the world in their heart, so that no man can find out the work that God maketh from the beginning to the end. I know that there is no good in them, but for a man to rejoice, and to do good in his life.