Think now about our personal relations — how we love our parents, our children, our life partners, our friends. To say that the moral worth of these individuals depends on the existence of God is to say that these people are, in themselves, worth nothing — that the concern we feel for their well being has no more ethical significance than the concern some people feel for their boats or their cars. It is to say that the historical connections we value, the traits of character and personality that we love — all count for nothing in themselves. Other people warrant our concern only because they are valued by someone else — in this case, God. (Imagine telling a child: “You are not inherently lovable. I love you only because I love your father, and it is my duty to love anything he loves.”)
What could make anyone think such things? Ironically, I think the answer is: the same picture of morality that lies behind atheistic nihilism. It’s the view that the only kind of “obligation” there could possibly be is the kind that is disciplined by promise of reward or threat of punishment. Such a view cannot find or comprehend any value inherent in the nature of things, value that could warrant particular attitudes and behavior on the part of anyone who can apprehend it. For someone who thinks that another being’s pain is not in itself a reason to give aid, or that the welfare of a loved one is not on its own enough to justify sacrifice, it is only the Divine Sovereign that stands between us and — as Hobbes put it — the war of “all against all.”
I want to close by conceding that there are things one loses in giving up God, and they are not insignificant. Most importantly, you lose the guarantee of redemption. Suppose that you do something morally terrible, something for which you cannot make amends, something, perhaps, for which no human being could ever be expected to forgive you. I imagine that the promise made by many religions, that God will forgive you if you are truly sorry, is a thought would that bring enormous comfort and relief. You cannot have that if you are an atheist. In consequence, you must live your life, and make your choices with the knowledge that every choice you make contributes, in one way or another, to the only value your life can have.
Some people think that if atheism were true, human choices would be insignificant. I think just the opposite — they would become surpassingly important.