Ecclesiastes 3:11-13

11He 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.

12I know that there is nothing better for them than to rejoice and to do good as long as they live;

13and also that every man should eat and drink and see and enjoy the good of all his labor—it is the gift of God.