This quote is from the 1948 Hitchcock film Rope and is said by Jimmy Stewart's character, publisher Rupert Cadell. He is at a dinner party hosted by Brandon Shaw and Phillip Morgan who were students at the prep school where Cadell was housemaster in the past. Cadell, worldly and cynical, has a great liking for the writings of Nietzsche- particularly the concept of an ubermensch (superman)- as well as Thomas de Quincey's satirical On Murder Considered As One Of The Fine Arts. As the evening wears on however, Cadell begins to suspect to his growing horror that his two former students have taken these philosophies out of the theoretical realm and applied them practically. They've committed a ghoulish murder as an intellectual exercise, based on the theory that superior persons need not be bound by the same moral laws that govern inferior, expendable ones.
The above words are spoken by Cadell early in the evening, facetiously, before he realises that something is very wrong. Afterwards, he is intensely ashamed that his nihilistic philosophies, though either spoken theoretically or in jest, have been used as a prompt and excuse for cold blooded murder.
**Incidentally, the "seven lively" arts that Cadell mentions are drama, drawing, movement, music, modelling, painting, and speech (a la Rudolph Steiner).**