“Getting ahead in a difficult profession requires avid faith in yourself. That is why some people with mediocre talent, but with great inner drive, go so much further than people with vastly superior talent.”

Honouree Announcement https://www.youtube.com/watch?v=TjTtG_muVhM (November 1, 2020)

ZNet commentary (35 November 1999) http://www.zmag.org/sustainers/content/1999-11/25zinn.htm
Context: Why should we accept that the "talent" of someone who writes jingles for an advertising agency advertising dog food and gets $100,000 a year is superior to the talent of an auto mechanic who makes $40,000 a year? Who is to say that Bill Gates works harder than the dishwasher in the restaurant he frequents, or that the CEO of a hospital who makes $400,000 a year works harder than the nurse or the orderly in that hospital who makes $30,000 a year? The president of Boston University makes $300,000 a year. Does he work harder than the man who cleans the offices of the university? Talent and hard work are qualitative factors which cannot be measured quantitatively.

Financial Times Interview (July 14, 2017)

Source: The Valley of Fear

Letter from Jamaica (Summer 1815)

Letter to Leopold Mozart (11 September 1778), from Wolfgang Amadé Mozart by Georg Knepler (1991), trans. J. Bradford Robinson [Cambridge University Press, 1994, ], p. 12.
Variant: A fellow of mediocre talent will remain a mediocrity, whether he travels or not; but one of superior talent (which without impiety I cannot deny that I possess) will go to seed if he always remains in the same place.

As quoted in Memorable Quotations: Jewish Writers of the Past (2005) edited by Carol A. Dingle.