Harry Potter and the Half-Blood Prince

"Lily Potter, when she sacrificed herself to save her son, created the greatest magic of all."

"Dark and difficult times lie ahead. Soon we must all face the choice between what is right and what is easy."

"It is our choices that show what we truly are, far more than our abilities."

"The mind is not a book, to be opened at will and examined at leisure."

"Youth cannot know how age thinks and feels."

"I am not concerned with pleasure or pain, but with the nature of the soul."

"Once again, you have allowed your emotions to distract you from what is really important."

"It is often our failings that define us as much as our accomplishments."

"Greatness inspires envy, envy engenders spite, spite spawns hate, and hate generates ruin."

"We are only as sick as our secrets."

"It is impossible to live without failing at something, unless you live so cautiously that you might as well not have lived."

"I have one last thing to tell you: the truth. It is a beautiful and terrible thing, and should therefore be treated with great caution."

"Voldemort himself created his own worst enemy, just as tyrants always do."

"There is nothing to be feared from a body, Harry, any more than there is anything to be feared from the dead."

"Of course it is happening inside your head, Harry, but why on earth should that mean that it is not real?"

"Dumbledore loved him, Dumbledore had chosen him, Dumbledore had told him secrets he told no other wizard."

"Dark and difficult times lie ahead. Soon we must all face the choice between what is right and what is easy."

"It is our choices that show what we truly are, far more than our abilities."

"History repeats itself to those who do not learn from it."

"Leadership is not about power, but service."

"The past shapes us, but does not define us."

"Time is the most precious commodity we possess."

"The greatest magic is the love we share with others."

"The mind is not a book to be written and read, but a garden to be cultivated."

"One can never have too many books."

"Youth cannot know how age thinks and feels, but old men are guilty if they forget what it was to be young."

"Words are, of course, the most powerful magic we have."

"It does not do to dwell on dreams and forget to live."

"The truth is a beautiful and terrible thing, and should therefore be treated with great caution."

"Help will always be given at Hogwarts to those who ask for it."