In one of the most powerful and poetic paragraphs I've ever read on human yearning and the hope of the gospel, Cornelius Plantinga (President of Calvin Theological Seminary) writes:
The truth is that nothing in this earth can finally satisfy us. Much can make us content for a time but nothing can fill us to the brim. The reason is that our final joy lies "beyond the walls of this world," as J.R.R Tolkien put it. Ultimate beauty comes not from a lover or a landscape or a home, but only through them. These earthly things are solid goods, and we naturally relish them. But they are not our final good. They point to what is higher up and further back…Even if we fall deeply in love and marry another human being, we discover that our spiritual and sexual oneness isn't final. It's wonderful, but not final. It might even be as good as human oneness can be, but something in us keeps saying "not this" or "still beyond"…What Augustine knew is that human beings want God…God has made us for himself. Our sense of God runs in us like a stream, even though, because of sin, we divert it toward other objects. We human beings want God even when we think that what we really want is a green valley, or a good time from our past, or a loved one. Of course we do want these things and persons, but we also want what's behind them. Our inconsolable secret, says C.S. Lewis, is that we are full of yearnings, sometimes shy and sometimes passionate, that point us beyond the things of earth to the ultimate reality of God.
Engaging God's World, pg. 5-7