“You are blinded,” said Dumbledore, his voice rising now, the aura of power around him palpable, his eyes blazing once more, “by the love of the office you hold, Cornelius! You place too much importance, and you always have done, on the so-called purity of blood! You fail to recognize that it matters not what someone is born, but what they grow to be!”

J. K. Rowling, Dumbledore in Harry Potter and the Goblet of Fire

"If you treat an individual as he is, he will remain how he is. But if you treat him as if he were what he ought to be and could be, he will become what he ought to be and could be."

Johann Wolfgang von Goethe