An old teacher once had a literary quotation about how cynics have truest hope/love for humanity. Who said it?

I looked on quotation pages for cynic/cynicism, but couldn't find it. It was an English literature teacher, so I believe that it was a culturally significant literary reference. Something like "a cynic has the most profound love/hope for humanity." It has been a decade though since I heard this quotation, and I am shaky on details.