We hear of the conversion of water into wine at the marriage in Cana as of a miracle. But this conversion is, through the goodness of God, made every day before our eyes. Behold the rain which descends from heaven upon our vineyards; there it enters the roots of the vines, to be changed into wine; a constant proof that God loves us, and loves to see us happy. The miracle in question was only performed to hasten the operation, under circumstances of present necessity, which required it.
Source:Letter to the Abbé Morellet (after July 5, 1779?)