Ecclesiastes 2:20-23

²⁰Therefore I began to cause my heart to despair concerning all the labor in which I had labored under the sun.

²¹For there is a man whose labor is with wisdom, with knowledge, and with skillfulness; yet he shall leave it for his portion to a man who has not labored for it. This also is vanity and a great evil.

²²For what does a man have of all his labor and of the striving of his heart, in which he labors under the sun?

²³For all his days are sorrows, and his travail is grief; yes, even in the night his heart takes no rest. This also is vanity.