Vanity of vanities…all our labors and efforts will one day amount to nothing. Now this assertion by Qoheleth, the  Preacher, can come across as a very negative and pessimistic approach to our lives here on earth. While labeling all human effort as vanity (a waste), the author of the book argues against finding any lasting value in the things of human life: not money, nor fame, nor pleasures, nor the possessions men and women spend their energies to acquire. Humanity will always be restless as it labors away, yet the fruits of its labors will amount to nothing (vanity), asserts the  Preacher. Well, many will out-rightly disagree with Qoheleth on this. They will argue that it is optimism, the hope for a better tomorrow, that keeps men and women from giving up on life. Those who disagree with the  preacher hold that it is the knowledge that hard work will ultimately bear fruit that keeps men and women laboring day and night. And finally, they will say, experience does show that everything is not vanity.
Be that as it may, we cannot just toss aside what Qoheleth is saying. Maybe there is a hidden message contained in the apparently overly-pessimistic stance of the book. Maybe it is true that our labors and hard work might not profit us personally. Maybe it is true that even as we toil and break our backs we will still live in grief and anxiety even when we are supposed to rest. But that should not hinder us from asking ourselves what is it that makes our hard work here on earth to be a mere waste of our time. Even as we toil in hard work, we should not forget even for a second the reason why God created us. We were created for a purpose, and our lives are not complete until we fulfill that purpose. 
From the Baltimore Catechism, we learn that God created us to know him, love him, and to serve him, so that ultimately we may rejoice with him in heaven. The purpose we were created to fulfill has God written all over it. God is the key to fulfilling that purpose. Our labors, efforts, skills, and knowledge become vanities when we exclude God from our lives. For without God to guide and direct us, we will fail to rejoice and make merry with the fruit of our labor. Without God to show us the right way, we will spend our lives asking ourselves what we are to do with the fruits of our labor. Without God to assure us that all will be well whenever we are beset by problems of this world, all our efforts will appear to us as mere vanity, and anxiety and worries will never part from us. It is the hope and trust we have in God that will become the difference at the end.