Harry Potter and the Deathly Hallows
"I'd say that it's one short step from 'Wizards first' to 'Purebloods first,' then to 'Death Eaters,'" replied Kingsley. "We're all human, aren't we? Every human life is worth the same, and worth saving." (22.78)
"I shall expect you and the Slytherins in the Great Hall in twenty minutes, also," said Professor McGonagall. "If you wish to leave with your students, we shall not stop you. But if any of you attempt to sabotage our resistance or take up arms against us within the castle, then, Horace, we duel to kill."
"Minerva!" he said, aghast.
"The time has come for Slytherin House to decide upon its loyalties," interrupted Professor McGonagall. (30.63)
"I regret it," said Voldemort coldly.
He turned away; there was no sadness in him, no remorse. It was time to leave this shack and take charge, with a wand that would now do his full bidding… Voldemort swept from the room without a backward glance… (32.121)