“So the boy . . . the boy must die?” asked Snape quite calmly.
“And Voldemort himself must do it, Severus. That is essential.”
Another long silence. Then Snape said, “I thought . . . all these years . . . that we were protecting him for her. For Lily.”
“We have protected him because it has been essential to teach him, to raise him, to let him try his strength,” said Dumbledore, his eyes still tight shut. “Meanwhile, the connection between them grows ever stronger, a parasitic growth: Sometimes I have thought he suspects it himself. If I know him, he will have arranged matters so that when he does set out to meet his death, it will truly mean the end of Voldemort.”
Dumbledore opened his eyes. Snape looked horrified. “You have kept him alive so that he can die at the right moment?”
“Don’t be shocked, Severus. How many men and women have you watched die?”
“Lately, only those whom I could not save,” said Snape. He stood up. “You have used me.”
“I have spied for you and lied for you, put myself in mortal danger for you. Everything was supposed to be to keep Lily Potter’s son safe. Now you tell me you have been raising him like a pig for slaughter —”
“But this is touching, Severus,” said Dumbledore seriously. “Have you grown to care for the boy, after all?”
“For him?” shouted Snape. “Expecto Patronum!"
From the tip of his wand burst the silver doe: She landed on the office floor, bounded once across the office, and soared out of the window. Dumbledore watched her fly away, and as her silvery glow faded he turned back to Snape, and his eyes were full of tears.
“After all this time?”
“Always,” said Snape.