Ecclesiastes 2:21-23

21For 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. 22What do people get for all the toil and anxious striving with which they labor under the sun?

23All their days their work is grief and pain; even at night their minds do not rest. This too is meaningless.