Stephen Garner's comment drove me to do some exploring - first via the net, then on my own bookshelves (ah, the inexpressible joy of having ALL my books out of boxes and on shelves!!!). The story referred to in my last post is by Harry Harrison and is titled, "The Streets of Ashkelon" (1961). The hero is an athiest Trader, John Garth, dismayed when a Catholic priest is delivered to the world on which he lives, a world populated by uniformly well-behaved beings who have never been 'lured' by any form of superstition and as a result are "happier and sane because of it." However the priest stays and following much discussion and reading of the Bible, the beings decide that they would like to believe, but need the help of a miracle - the kind of miracle which brings a whole world to belief. And so in eager anticipation they crucify the priest and bury him (having bound the Trader so he would not interfere), waiting for the miracle of resurrection to take place. Afterwards, Itin, a questioning alien asks the Trader whether they had done the right thing - whether the priest would be raised, to which the Trader answers negatively.
"Then we will not be saved? We will not become pure?" [asks Itin]
"You were pure," Garth said, in a voice somewhere between a sob and a laugh. "That's the horrible, ugly, dirty part of it. You were pure. Now you are..."
"Murderers," Itin said, and the water ran down from his lowered head and streamed away into the darkness.