Ecclesiastes 2:20-23

So my heart began to despair over all my toilsome labor under the sun. For a person may labor with wisdom, knowledge and skill, and then they must leave all they own to another who has not toiled for it. This too is meaningless and a great misfortune. What do people get for all the toil and anxious striving with which they labor under the sun? All their days their work is grief and pain; even at night their minds do not rest. This too is meaningless.