Ecclesiastes 2:19-23

And who knows whether he will be wise or a fool? Yet he will have control over all the fruit of my labor for which I have labored by acting wisely under the sun. This too is futility.

Therefore I completely despaired over all the fruit of my labor for which I had labored under the sun.

When there is a person who has labored with wisdom, knowledge, and skill, and then gives his legacy to one who has not labored for it; this too is futility and a great evil.

For what does a person get in all his labor and in his striving with which he labors under the sun?

Because all his days his activity is painful and irritating; even at night his mind does not rest. This too is futility.