Ecclesiastes 8:14-17

There is a vanity which is done upon the earth, that there are righteous men unto whom it happeneth according to the work of the wicked; again, there are wicked men to whom it happeneth according to the work of the righteous: I said that this also is vanity. Then I commended mirth, because a man hath no better thing under the sun, than to eat, and to drink, and to be joyful: for that shall abide with him in his labor all the days of his life which God hath given him under the sun. When I applied my heart to know wisdom, and to see the business that is done upon the earth (for also there is that neither day nor night seeth sleep with his eyes), then I beheld all the work of God, that man cannot find out the work that is done under the sun: because however much a man labor to seek it out, yet he shall not find it; yea moreover, though a wise man think to know it, yet shall he not be able to find it.