Ecclesiastes 8:17 in the World English Bible
then I saw all the work of God, that man can’t find out the work that is done under the sun, because however much a man labors to seek it out, yet he won’t find it. Yes even though a wise man thinks he can comprehend it, he won’t be able to find it.
Context
16 When I applied mine 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:)
17 Then I beheld all the work of God, that a man cannot find out the work that is done under the sun: because though a man labour to seek it out, yet he shall not find it; yea further; though a wise man think to know it, yet shall he not be able to find it.