The vanity of life from the naturalist's perspective (chapter 3)
This chapter is the natural man's view of the weary round of life. Naturalism is the "idea or belief that only natural (as opposed to supernatural or spiritual) laws and forces operate in the world."
There is a time for everything (v. 1–8)
The natural man says, "It is just life. Things happen to us. There is no purpose or design in it. It is all chance."
But we know from other Scriptures that God is in control, and that He has a plan (Jer.29:11; Dan. 2:21; Amos 3:6; Job 1:10; Rom. 8:28; Matt. 5:45–48).
Man's God-given task (v. 9–15)
God has created humanity and the world. He has given us work to do. We are to do that work, rejoice, do good, eat, drink, and enjoy the results of our labor.
The conclusion of the materialist (v. 16–22)
Qoholeth is discouraged because everywhere he looks he sees wickedness. But he knows that there is a season for everything, and though the wicked may have a season of prosperity, there will come a season of judgment.