In article , Tom Watson wrote:
Righteous Indignation
[snip]

To those who profess to be without sin and therefore deem themselves
qualified to cast the first stone - I would suggest that you have not
been adequately tempted.

"The weakest of all weak things is virtue that has never been tested in the
fire."

I comment to your attention the source of this quotation, a short story by
Mark Twain entitled "The Man Who Corrupted Hadleyburg".