Ecclesiastes 8:15-17

Then I commended pleasure and enjoyment, because a man [without God] has no better thing under the sun than to eat and to drink and to be merry, for this will stand by him in his toil through the days of his life which God has given him under the sun. When I applied my mind to know wisdom and to see the activities [of mankind] that take place upon the earth—how some men seem to sleep neither day nor night— and I saw all the work of God, I concluded that man cannot discover the work that is done under the sun. Even though man may labor in seeking, he will not discover; and [more than that], though a wise man thinks and claims he knows, he will not be able to find it out. [Deut 29:29; Rom 11:33]