Ecclesiastes 8:16-17 meaning

Solomon directed his thought, emotions, and will to his understanding of wisdom. This he aimed at comprehending (to see) all the "business" (task) done on the earth, which was every work of God done under the sun. He concluded that no man would ever be able to discover the complete picture of God's actions in this world. We cannot fully know the what and why. His ways are higher than our ways.

As the Apostle Paul said on this topic:

"Oh, the depth of the riches both of the wisdom and knowledge of God! How unsearchable are His judgments and unfathomable His ways! For who has known the mind of the Lord, or who became his counselor? Or who has first given to him that it might be paid back to him again?" (Romans 11:33-35, quoting Isaiah 40:13, Job 41:11).

No combination of time, labor, and wisdom can give humanity all the answers. Human reason and experience will always fall short of comprehending God. Man may toil to understand, even never sleep day or night, spending twenty-four hours a day thinking about it—but he cannot fully grasp God's ways. No matter what the wise man might say. The wise may make a claim knowledge, might say I know, but the claim will be empty. He still cannot discover.

The uses of should in these verses connects three actions that will be futile in fulfilling the longing of the heart to know wisdom: a wise man should never sleep, should seek laboriously and should say "I know." These actions to seek to discover God's ways will be futile. If one might never sleep day or night, we still cannot discover the ways of God through reason and experience. Some do make claims that they know the work God has done under the sun. But their claims are hollow.

Solomon has been seeking to discover the work God does from beginning to end (Ecclesiastes 3:11). He discovered it couldn't be found through human reason and experience. Rather, understanding begins with faith—the fear of God. Solomon's strategy is to explain that while we can't have answers to all of our "how does this fit with that" questions, we can still enjoy life as a good gift from a gracious God when our foundation for understanding begins with faith and gratitude rather than reason and experience. To depend on self is a quest that is like grasping vapor ("hebel"). To depend on God transforms the mystery ("hebel") into an opportunity and source of joy that brings meaning and fulfillment to the human experience.