WHEN GOD TOLD ABRAHAM, who was a hundred at the time, that at the age of ninety his wife, Sarah, was finally going to have a baby, Abraham came close to knocking himself out—"fell on his face and laughed," as Genesis puts it (17:17). In another version of the story (18:8ff.), Sarah is hiding behind the door eavesdropping, and here it's Sarah herself who nearly splits a gut—although when God asks her about it afterward, she denies it. "No, but you did laugh," God says, thus having the last word as well as the first. God doesn't seem to hold their outbursts against them, however. On the contrary, God tells them the baby's going to be a boy and they are to name him Isaac. Isaac in Hebrew means "laughter.”
Why did the two old crocks laugh? They laughed because they knew only a fool would believe that a woman with one foot in the grave was soon going to have her other foot in the maternity ward. They laughed because God expected them to believe it anyway. They laughed because God seemed to believe it. They laughed because they half believed it themselves. They laughed because laughing felt better than crying. They laughed because if by some crazy chance it just happened to come true, they would really have something to laugh about, and in the meanwhile it helped keep them going.
Faith is "the assurance of things hoped for, the conviction of things not seen," says the Letter to the Hebrews (11:1). Faith is laughter at the promise of a child called Laughter.
Faith is better understood as a verb than as a noun, as a process than as a possession. It is on-again-off-again rather than once-and-for-all. Faith is not being sure where you're going, but going anyway. A journey without maps. Paul Tillich said that doubt isn't the opposite of faith; it is an element of faith.
I have faith that my friend is my friend. It is possible that all his motives are ulterior. It is possible that what he is secretly drawn to is not me, but my wife or my money. But there's something about the way I feel when he's around, about the way he looks me in the eye, about the way we can talk to each other without pretense and be silent together without embarrassment, that makes me willing to put my life in his hands, as I do each time I call him friend.
I can't prove the friendship of my friend. When I experience it, I don't need to prove it. When I don't experience it, no proof will do. If I tried to put his friendship to the test somehow, the test itself would queer the friendship I was testing. So it is with the Godness of God.
The five so-called proofs for the existence of God will never prove to unfaith that God exists. They are merely five ways of describing the existence of the God you have faith in already.
Almost nothing that makes any real difference can be proved. I can prove the law of gravity by dropping a shoe out the window. I can prove that the world is round if I'm clever at that sort of thing—that the radio works, that light travels faster than sound. I cannot prove that life is better than death or love better than hate. I cannot prove the greatness of the great or the beauty of the beautiful. I cannot even prove my own free will; maybe my most heroic act, my truest love, my deepest thought are all just subtler versions of what happens when the doctor taps my knee with his little rubber hammer and my foot jumps.
Faith can't prove a damned thing. Or a blessed thing either.