Ecclesiastes 3:9-11

Amplified Bible

⁹ What profit is there for the worker from that in which he labors? ¹⁰ I have seen the task which God has given to the sons of men with which to occupy themselves.

God Set Eternity in the Heart of Man

¹¹ He has made everything beautiful and appropriate in its time. He has also planted eternity [a sense of divine purpose] in the human heart [a mysterious longing which nothing under the sun can satisfy, except God]—yet man cannot find out (comprehend, grasp) what God has done (His overall plan) from the beginning to the end.