The Dark Arts are many, varied, ever-changing, and eternal. Fighting them is like fighting a many-headed monster, which, each time a neck is severed, sprouts a head even fiercer and cleverer than before. You are fighting that which is unfixed, mutating, indestructible.
“That is just as well, Potter,” said Snape coldly, “because you are neither special nor important, and it is not up to you to find out what the Dark Lord is saying to his Death Eaters.” “No — that’s your job, isn’t it?” Harry shot at him. He had not meant to say it; it had burst out of him in temper. For a long moment they stared at each other, Harry convinced he had gone too far. But there was a curious, almost satisfied expression on Snape’s face when he answered. “Yes, Potter,” he said, his eyes glinting. “That is my job.”
“You are here to learn the subtle science and exact art of potion-making. As there is little foolish wand-waving here, many of you will hardly believe this is magic. I don’t expect you will really understand the beauty of the softly simmering cauldron with its shimmering fumes, the delicate power of liquids that creep through human veins, bewitching the mind, ensnaring the senses. . . I can teach you how to bottle fame, brew glory, even stopper death — if you aren’t as big a bunch of dunderheads as I usually have to teach.”
“Albus Severus,” Harry said quietly, so that nobody but Ginny could hear, and she was tactful enough to pretend to be waving to Rose, who was now on the train, “you were named for two headmasters of Hogwarts. One of them was a Slytherin and he was probably the bravest man I ever knew.”
“Then you will find yourself easy prey for the Dark Lord! Fools who wear their hearts proudly on their sleeves, who cannot control their emotions, who wallow in sad memories and allow themselves to be provoked this easily — weak people, in other words — they stand no chance against his powers! He will penetrate your mind with absurd ease, Potter!”
Mr. Moony presents his compliments to Professor Snape, and begs him to keep his abnormally large nose out of other people’s business.
Mr. Prongs agrees with Mr. Moony, and would like to add that Professor Snape is an ugly git.
Mr. Padfoot would like to register his astonishment that an idiot like that ever became a professor.
Mr. Wormtail bids Professor Snape good day, and advises him to wash his hair, the slimeball.
“That is the second time you have spoken out of turn, Miss Granger,” said Snape coolly. “Five more points from Gryffindor for being an insufferable know-it-all.”
Hermione went very red, put down her hand, and stared at the floor with her eyes full of tears. It was a mark of how much the class loathed Snape that they were all glaring at him, because every one of them had called Hermione a know-it-all at least once, and Ron, who told Hermione she was a know-it-all at least twice a week, said loudly, “You asked us a question and she knows the answer! Why ask if you don’t want to be told?”
“Her son lives. He has her eyes, precisely her eyes. You remember the shape and color of Lily Evans’s eyes, I am sure?”
“DON’T!” bellowed Snape. “Gone… dead…”
“Is this remorse, Severus?”
“I wish… I wish I were dead…”
“And what use would that be to anyone?” said Dumbledore coldly.
There was a long pause, and slowly Snape regained control of himself, mastered his own breathing. At last he said, ‘Very well. Very well. But never – never tell, Dumbledore! This must be between us! Swear it! I cannot bear… especially Potter’s son… I want your word!’
‘My word, Severus, that I shall never reveal the best of you?’ Dumbledore sighed, looking down into Snape’s ferocious, anguished face. ‘If you insist …’
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 somebody else had spoken Snape’s name, quite softly.
“Severus . . .”
The sound frightened Harry beyond anything he had experienced all evening. For the first time, Dumbledore was pleading.
Snape gazed for a moment at Dumbledore, and there was revulsion and hatred etched in the harsh lines of his face.
“Severus . . . please . . .”
Snape raised his wand and pointed it directly at Dumbledore.
A jet of green light shot from the end of Snape’s wand and hit Dumbledore squarely in the chest. Harry’s scream of horror never left him; silent and unmoving, he was forced to watch as Dumbledore was blasted into the air. For a split second, he seemed to hang suspended beneath the shining skull, and then he fell slowly backward, like a great rag doll, over the battlements and out of sight.”