You have to be free to fail in this world.

Professor,” Harry gasped. “Your bird — I couldn’t do anything — he just caught fire —

Yeah, Quirrell was a great teacher. There was just that minor drawback of him having Lord Voldemort sticking out of the back of his head!

Sirius looked slightly disconcerted for a moment, then said, "I'll look for him later, I expect I'll find him upstairs crying his eyes out over my mother's old bloomers or something... Of course, he might have crawled into the airing cupboard and died... But I mustn't get my hopes up.

If all goes well, you will be able to save more than one innocent life tonight.

Just — just to be clear,” he said. “You want to leave Tonks at her parents’ house and come away with us?” “She’ll be perfectly safe there, they’ll look after her,” said Lupin. He spoke with a finality bordering on indifference. “Harry, I’m sure James would have wanted me to stick with you.” “Well,” said Harry slowly, “I’m not. I’m pretty sure my father would have wanted to know why you aren’t sticking with your own kid, actually.

At that moment, Harry fully understood for the first time why people said Dumbledore was the only wizard Voldemort had ever feared. The look upon Dumbledore's face as he stared down at the unconscious form of Mad-Eye moody was more terrible than Harry could have ever imagined. There was no benign smile upon Dumbledore's face, no twinkle in the eyes behind the spectacles. There was cold fury in every line of the ancient face; a sense of power radiated from Dumbledore as though he were giving off burning heat.