Quote 4
"You show spirit and bravery, and you come of noble stock. You will make a very valuable Death Eater. We need your kind, Neville Longbottom."
"I'll join you when hell freezes over," said Neville. "Dumbledore's Army!" he shouted, and there was an answering cheer from the crowd… (36.54)
Neville's good-evil compass never wavers, even when Voldemort tries to tempt him over to the dark side. It would never work – he's a true Gryffindor through and through, and is loyal and courageous to the bone. He's certainly not the second coming of Peter Pettigrew, as we once feared.
Quote 5
"Is it love again?" said Voldemort, his snake's face jeering. "Dumbledore's favorite solution, love, which he claimed conquered death, though love did not stop him falling from the tower and breaking like an old waxwork? Love, which did not prevent me from stamping out your Mudblood mother like a cockroach, Potter – and nobody seems to love you enough to run forward this time and take my curse. So what will stop you from dying now when I strike?" (36.102)
After all these years, Voldemort still hasn't learned his lesson – love does matter, and it is a kind of power he'll never be able to master. Love as a motivation is what has undone him; we've seen it in everyone who's betrayed the Dark Lord, like Snape and Narcissa; people can't help but love, and it's the most powerful force in the world.
Quote 6
"Where no proven Wizarding ancestry exists, therefore, the so-called Muggle-born is likely to have obtained magical power by theft or force.
"The Ministry is determined to root out such usurpers of magical power…" (11.38)
Voldemort's desire to get rid of all non-pureblood Wizards is really a problem of identity – he's taken it upon himself to decide who is really a wizard and who isn't. However, there's the problem of personal identity – Muggle-born wizards really are just as magical as purebloods, and Voldemort's new restrictions are simply lies.