Ecclesiastes 2:20-23

²⁰Therefore I turned about to cause my heart to give up thinking of all the toil wherewith I had toiled under the sun.

²¹For there is many a man whose toil is in wisdom, and in knowledge, and with energy; yet to a man that hath not toiled therefore must he give it as his portion. Also this is vanity and a great evil.

²²For what doth a man obtain of all his toil, and of the torture of his heart, wherewith he toileth under the sun?

²³For all his days are full of pains, and vexation is mingled with his employment: yea, even in the night his heart taketh not rest. Also this is vanity.