Someone once asked Bruce whether or not he had a black belt, to which he responded, "I don't have any belt, whatsoever. That is just a certificate. Unless you can really do it - that is, defend yourself successfully in a fight - that belt doesn't mean anything. I think it might be useful to hold your pants up, but that's about it."
came across this quote in the book Everybody was Kung Fu Fighting by Vijay Prashad.