Ecclesiastes 2:20-23

So I turned about and gave my heart up to despair over all the toil of my labors under the sun, because sometimes a person who has toiled with wisdom and knowledge and skill must leave everything to be enjoyed by someone who did not toil for it. This also is vanity and a great evil. What has a man from all the toil and striving of heart with which he toils beneath the sun? For all his days are full of sorrow, and his work is a vexation. Even in the night his heart does not rest. This also is vanity.