[God] has put eternity into man's heart, yet so that he cannot find out what God has done from the beginning to the end. (Ecclesiastes 3:11b ESV)
The author’s worldview accepted that there was some type of existence beyond the present life. He believed that a person was born with an innate—God given—sense of ‘eternity’ (Hebrew olam ‘forever’ or ‘everlasting’). This deep rooted feeling is accompanied by an uneasy sense, ‘disquietness’, at the inability to figure out or comprehend God’s ways. There are certainly aspects of God’s nature and purpose that can be discerned, but human ability in this is limited (see Deuteronomy 29:29). The quest of the finite for the infinite, unless aided by the Infinite, is bound to end in disappointment.
Thus the author concludes that the course a person should set is not to give way to despair or disillusionment at what they cannot know, but to recognize what God has given that may be known and enjoyed—the simple pleasures of life as stated in 3:12-13—to “be joyful and to do good” and to eat, drink and enjoy our work, “this is God's gift to man.” It isn’t that God doesn’t intend for a person to have or know more, but that these ‘basics’ are His gift to all.
Man always chases extremes. On the one hand a person can become so caught up in the pursuit of eternity that they forego or miss the pleasures of life which God has given in the ‘now’. Perhaps you know someone like this—someone who lives an ascetic or ‘Spartan’ lifestyle as they pursue piety or spirituality. I think of Symeon the Stylite who lived on a platform at the top of a pillar in the desert.
On the other hand, one can become so consumed with earthly pleasures and pursuits that they lose sight of eternity completely. Here I am reminded of the parable told by Jesus in Luke 12:16-21 in which a wealthy man focuses all his energy and attention upon his temporal life with no thought to his condition beyond life: “But God said to him, 'You fool! This very night your life will be demanded from you. Then who will get what you have prepared for yourself?'” (Luke 12:20 NIV). In a sobering conclusion Jesus tells us that “this is how it will be with anyone who stores up things for himself but is not rich toward God.” (Luke 12:21 NIV)
God has given us this sense of something ‘beyond the sun’—something eternal—to remind us that life has a deeper, more significant meaning. He has also given us pleasures in this life that we may enjoy our days and years. There is nothing wrong with enjoying the things of the world, just as there is no shame in the pursuit of the spiritual, but there must be balance as we seek eternity while living life now. We must look for God, the giver of all and the hope for our significance.