The Pardoner uses the message "stupidity is the root of all evil" in
his  sermon to sway the people to hand him some of there money.
Within this sermon he uses 3 vices within stupidity which are
gluttony, gambling, and swearing, and he uses them through the story
he tells of the men trying to find death.  Within the story you have
to pick out the three vices.  At first the pardoners tells you they
are doing these things at the beginning of the story before they went
on their journey but you later see they carry these traits over to the
journey they go on.  You can se gluttony in the fact that all the men
want the money to themselves, and will do anything, including kill
another to get what they want.   Next, you see gambling in the fact
that they use "who pulls the shortest stick" as a method of
determining who is going to get food and wine for them to have for the
night. Lastly, they swear at the old man and make fun of him on their
way to find death, but he is the reason they found death, proving that
the reason the pardoner's story is effective to showcase that all
these people may be easily living in sin.