Origin of quote 'anything you say about god you must be willing to say on a pile of dead babies'

I am paraphrasing the quote, and I tried to cut it down so that it would fit in the title.

The quote was something like that ‘anything you say about god you have to be willing to say on top of a pile of dead children’, in reference, I assume, to the billions of humans who died as infants and toddlers in human history. If you talk about ‘learning lessons’ or ‘eternal love’ or whatever you have to be willing to say it in that context.

Who originated the quote, what is the exact quote, and what was the context?