How we cite our quotes: Citations follow this format: (Chapter.Paragraph)
Quote #4
"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)
Well said, Kingsley. He touches upon the essential difference between good and evil, or between Order of the Phoenix and Death Eater here – the Order stands for equality, while the Death Eaters represent prejudice and an inhuman and unjust elitism.
Quote #5
"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)
Slytherin House, led by Professor Slughorn, is forced to decide whose side it's on – the school's, or its most famous alumnus's. Professor McGonagall's ultimatum makes it pretty clear that the time for moral ambiguity is past.
Quote #6
"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)
Voldemort's true depths of evil are really revealed by his callous murder of Snape, who he thought was his faithful servant all these years. He truly has progressed beyond "the usual evil" – he's past all human feeling.