Ecclesiastes Chapter 8 Verse 16 and 17

Ecc 8:16 When I gave my heart to know wisdom and to see the task which has been done on the earth (even though one should never sleep day or night), Ecc 8:17 and I saw every work of God, I concluded that man cannot discover the work which has been done under the sun. Even though man should seek laboriously, he will not discover; and though the wise man should say, "I know," he cannot discover.