I'm not going to xxx out any words in what follows, so if you are offered by reading certain words, stop reading.

Richard Pryor was a comedian---one of the best and most influential comedians America has had. His line is a joke about how there are good black people (negroes) and bad black people (niggers). The good ones could be trusted to stay out a little longer. The funny part is that even the good ones (negroes) still had a curfew.

Years later, Chris Rock (another important comedian and one who has been influenced by Pryor) had a similar bit in one of his shows about the differences between black people and niggers. You can watch Rock's bit here (it's hilarious): https://youtu.be/f3PJF0YE-x4.