Love: To extend one's self for the purpose of nurturing one's own or another's spiritual growth.
If we postulate that our capacity to love, this urge to grow and evolve, is somehow "breathed into" us by God, then we must ask to what end. Why does God want us to grow? What are we growing toward? Where is the end point, the goal of evolution? What is it that God wants of us? ... all of us who postulate a living God and really think about it eventually come to a single terrifying idea: God wants us to become Himself (or Herself or Itself). We are growing toward godhood. God is the goal of evolution. It is God who is the source of evolutionary force and God who is the destination. That's what we mean when we say that he is the Alpha and the Omega, the beginning and the end.
When I say that this is a terrifying idea I was speaking mildly. ... For no idea ever came to the mind of man which places upon us such a burden. It is the single most demanding idea in the history of mankind. Not because it is difficult to conceive; to the contrary, it is the essence of simplicity. But because if we believe it, it then demands from us all that we can possibly give, all that we have. It is one thing to believe in a nice old God who will take good care of us from a lofty position of power which we ourselves could never begin to attain. It is quite another to believe in a God who has in mind for us precisely that we should attain His position, His power, His wisdom, His identity.
As long as we believe that godhood is an impossible attainment for ourselves, we don't have to worry about our spiritual growth, we don't have to push ourselves to higher and higher levels of consciousness and loving activity; we can relax and just be human. If God is in heaven and we are down here and never the twain shall meet, we can let Him have all the responsibility for evolution and the directorship of universe. ... Nonetheless as soon as we believe it is possible for man to become God, we can really never rest for long, never say, OK, my job is finished, my work is done.
Excerpt from The Road Less Traveled by M. Scott Peck