Solomon had unequaled wisdom, the supreme position, unsurpassed wealth, and hundreds of wives and concubines, and fell in the indulgence of his lust to an unparalleled extent. Through all the positive and negative experiences of the human life under the sun, his thought was deeply impressed and occupied with the central thought of this book, that is, the vanity of vanities of the human life under the sun in its falling away from God. Man was created by God with the highest and most noble purpose, that is, to express Him in the resemblance of Him in His life, nature, and expression. But God's enemy, Satan the devil, came in to inject himself as sin into the man created by God for His purpose. Through this fall of man, man and all the created things that had been committed by God to his dominion were brought into the slavery of corruption, made subject to vanity (Rom. 8:20-21). Thus, the human life in the corrupted world also became a vanity, a chasing after wind. The writer Solomon had fully realized this and stressed this to the uttermost in his description. Yet he was not fully disappointed in this, but rather he instructed men that there is a way to get out of this vanity, that is, to come back to God and take God as man's everything, redemption, life, wealth, enjoyment, pleasure, and satisfaction, that man still may be used by God to fulfill His original purpose in man for the fulfillment of His eternal economy (Eccl. 12:13-14).
Ecclesiastes 1:1-11 is the opening word.
Verse 1 indicates that the writer was Solomon, the son of David, king in Jerusalem—the Preacher.
In verses 2 through 11 we see that the theme of this book is vanity of vanities.
All the works of man under the sun are done in cycle (vv. 3-4). Every day the sun rises and goes down. Every year one season follows another. Parents bring forth children and eventually die. The children grow and bring forth children of their own, and then they die. The cycle goes on and on, with nothing new.