The quote in the Bible says the LOVE of money is the root of all evil. I saw this misquoted a couple days ago in Dickens, and here it is again.
"Money, John,' said Mr. Pecksniff, `is the root of all evil. I grieve to see that it is already bearing evil fruit in you."

Chaucer got it right, though, if I remember - cupiditas radix malorum est was the motto of the Pardoner's (or was it the Reeve's?) tale. For what it's worth, a variant on that tale was used by Kipling in his Second Jungle Book and the story of "The King's Ankus".

While on the subject, why is the word cupidity so rare. It would be the perfect substitute, wouldn't it?

"Cupidity is the root of all evil"

So there...

cheer

the sunshine warrior

Dear Shanks: Using your clues, search for "Chaucer Pardoner cupiditas" yielded:
"Moreover, a careful reading of The Pardoners Tale shows that it is an apposite illustration of major Augustinian themes, especially those expounded in the early, obscure treatise On Lying. The Pardoners avowal that his main theme is the Pauline aphorism Radix Malorum est cupiditas (334, 426, I Timothy 6:10) and subsequent description of his modus operandi have thrown many critics off the scent of what truly ails and peynes (330) his character."

why is the word cupidity so rare

Another of those words that don't sound like what they mean.

Webster's 1913 Dictionary

Definition: \Cu*pid"i*ty\ (k?-p?d"?-t?), n. [F. cupidite, L.
cupiditas, fr. cupidus longing, desiring, fr. cupere to long
for, desire. See {Covet}.]
1. A passionate desire; love. [Obs.]

2. Eager or inordinate desire, especially for wealth; greed
of gain; avarice; covetousness.

With the feelings of political distrust were mingled
those of cupidity and envy, as the Spaniard saw the
fairest provinces of the south still in the hands of
the accursed race of Ishmael. --Prescott.

Too few remember that Cupid got his name from "cupere".

Dear Doc

My understanding ('did' Chaucer years ago in college and may have forgotten), is that the Pardoner was guilty of hypocrisy, in the main. His tale, which illustrated the treachery associated with greed, was topped and tailed by him with all sorts of sententious claptrap, when he was actually making money hand over fist selling pardons. Chaucer was an acute observer of character (as is frequently said), and some of his remarks definitely raise a rueful chuckle of recognition.

cheer

the sunshine warrior

Dear Shanks: I haven't read the Pardoner's Tale, but I have read that to put it bluntly, he had a license to steal.
The Devil can quote Scriptures to his purpose.