His priority did not seem to be to teach them what he knew, but rather to impress upon them that nothing, not even... knowledge, was foolproof.
J. K. RowlingYouth cannot know how age thinks and feels. But old men are guilty if they forget what it was to be young.
J. K. RowlingOh, that,' said Ginny, giggling. 'Well-Percy's got a girlfriend.' Fred dropped a stack of books on George's head. 'What?' 'It's that Ravenclaw prefect, Penelope Clearwater,' said Ginny. 'That's who he was writing to all last summer. He's been meeting her all over the school in secret. I walked in on them kissing in an empty classroom one day. He was so upset when she was-you know-attacked. You won't tease him, will you?' she added anxiously. 'Wouldn't dream of it,' said Fred, who was looking like his birthday had come early.
J. K. Rowling