"All Cretans are liars. I was told this by a Cretan."This, as you may know, is a centuries-old logical quandry. Are all Cretans liars? If the above quote is all the info you've got, it's impossible to answer.
"Be suspicious of power. I was told this by a tenured Princeton University professor."I really was so advised by just such a professor - along with an auditorium full of eager young minds who may have been able to make sense of the statement - but I'm stumped.