Let Your Lives Speak?

In the bookstore today a customer called in and asked about "Let your lives speak," a phrase frequently attributed to George Fox (it's the source of a book title, "Lives that Speak"). While a quick Google search finds lots of pages where people say things like "as George Fox said, you should 'let your lives speak,'" no one actually gives details of when and where he said it. The phrase seems to sit only by itself, with no passages before or after it. A few sites claim it was part of his message on Firbank Fell but no one cites a source. Sitting on the same Palm Pilot as the Yardbirds MP3s is Fox's Journal (Jones edition) and a keyword search doesn't pick up "lives that speak" or "let your lives speak" anywhere. Smells fishy, like another one of those too-good-to-be-true Fox quotes. Can anyone document that it's real?

PS: I fly bright and early tomorrow morning for this year's Quakers Uniting in Publications meeting, in Oregon. I don't know what internet access I'll have so my apologies if new comments have to sit for a few days.