"We seem to be at cross-purposes here," Mack said. "I doubt not that you are Faust. Yet I am Faust, too, on the authority of no less a person than Mephistopheles." .The Context: A thug by the name of Mack the Club has accepted Mephistophelean bargain that should have been offered to Faust, and Faust is confronting him about it.
"Mephistopheles was mistaken!"
"When the great ones make mistakes, those mistakes become law."
Faust drew himself to his full height, which was rather shorter than Mack's, and said, "Must I listen to this casuistic palaver from one who speaks in my name? By the powers, I'll have vengeance if you don't vacate immediately and leave this game to the player for whom it was intended, namely, me."
"You think highly of yourself, that much is evident," Mack said. "But as to who was chosen, it seems to, be me. You can argue till kingdom come and you won't change that."
"Argue? I'll do a lot more than argue! I'll blast you with spells of greatest puissance, and your punishment will be most hideously condign."
"Will be what?" Mack asked.
"Condign. It means fitting. I intend to give you a punishment worthy of your transgression."
"You know a lot of words honest folk never use," Mack said hotly.
Why I like it: I enjoy Zelazny's sense of humor (if indeed this is Zelazny's writing. Sheckley rewrote some of Zelazny's contributions to the story), and Mack is a wonderful foil to Faust in this underrated story.