The book of Ecclesiastes contains Proverbs, maxims, sayings, and is largely an autobiographical story. Solomon wrote it late in his life, approximately 935 B.C. He had become aware of the mistakes that he made throughout his life and began to document them. The purpose of Ecclesiastes is to spare future generations the suffering and misery of seeking after foolish, meaningless, materialistic emptiness, and to offer wisdom by discovering truth in seeking after God.
It appears that Solomon once again, wants to teach the reader wisdom, “I set my mind to seek and explore by wisdom concerning all that has been done under heaven. It is a grievous task which God has given to the sons of men to be afflicted with” (1:13).
• Chapter 1-2, deal with Solomon’s personal experiences throughout his life. He describes that everything he sought was selfish pleasure and meant nothing eternally. Generally, he speaks concerning the meaning of life, “I have seen all the works which have been done under the sun, and behold, all is vanity and striving after the wind.” (1:14). Solomon, the man whom God gave the most wisdom; sought after, researched, and tried everything in an attempt to find lasting happiness, and came to this conclusion: “All that my eyes desired I did not refuse them. I did not withhold my heart from any pleasure, for my heart was pleased because of all my labor and this was my reward for all my labor. Thus I considered all my activities which my hands had done and the labor which I had exerted, and behold all was vanity and striving after the wind and there was no profit under the sun.” (2:10-11).
• In chapters 3-5, Solomon gives common explanations and observations. One in particular is 5:15, “As he had come naked from his mother’s womb, so will he return…”, speaking of everyone who dies takes nothing with him; possessions, in the end, are ultimately useless. As tough as it is, our sinful nature naturally gravitates toward materialism.
• Chapters 6-8, Solomon gives advice for having a meaningful life, “Consider the work of God, for who is able to straighten what He has bent?” (7:13).
• In chapters 9-12, Solomon writes a conclusion that clears up the entire book, everyone will eventually die and all the deeds of man are vanity (useless) without God; our obedience must be to Him. “The conclusion, when all has been heard, is: Fear God and keep His commandments, because this applies to every person.” (12:13). Source