The Egg And The Eye
Snape was looking down at Moody, and Harry couldn’t see the expression on his face. For a moment, nobody moved or said anything. Then Snape slowly lowered his hands.
“I merely thought,” said Snape, in a voice of forced calm, “that if Potter was wandering around after hours again… it’s an unfortunate habit of his… he should be stopped. For – for his own safety.”
“Ah, I see,” said Moody softly. “Got Potter’s best interests at heart, have you?”
Harry Potter and The Goblet Of Fire [Chapter 25: The Egg and The Eye]
I never realized that Snape’s line means something!