That version above was spoken by John Houseman in the movie The Paper Chase. They inserted it in the middle of the movie.
It's from John Jay Osborne's book "The Paper Chase" written based on his experiences at Harvard Law. I think another competing book called One-L is better.
Here's the passage which appears in italics ahead of chapter one:
In the few days between arrival at Harvard Law School and the first classes, there are rumors. And stories. About being singled out, made to show your stuff. Mostly, they're about people who made some terrible mistake. Couldn't answer a question right. One concerns a boy who did a particularly bad job. His professor called him down to the front of the class, up to the podium, gave the student a dime and said, loudly: "Go call your mother, and tell her you'll never be a lawyer."
Sometimes the story ends here, but the way I heard it, the crushed student bowed his head and limped slowly back through the one hundred and fifty students in the class. When he got to the door, his anger exploded. He screamed-- "You're a son of a bitch, Kingsfield."
"That's the first intelligent thing you've said," Kingsfield replied. "Come back. Perhaps I've been too hasty."