I Found It!

While touring all those great churches in Rome, I kept recalling this passage from my reading, but I couldn't for the life of me remember where I'd seen it. Here's the passage. I found it in Joseph Epstein's In a Cardboard Belt!
A character touring Italy in one of [Henry James'] stories, upon remarking regretfully about not being Catholic to another character, says, "What a different thing this visiting of churches would be for us, if we occasionally felt the prompting to fall to our knees.
Amen.
So to speak.