“One should cultivate good habits of memory, for it is capable of making existence a Paradise or an Inferno.”

“Never compete with someone who has nothing to lose.”

“Friendship multiplies the good of life and divides the evil.”

“True friendship multiplies the good in life and divides its evils. Strive to have friends, for life without friends is like life on a desert island... To find one real friend in a lifetime is a goo...”

“Though such authority and respect shouldn't be handed to all and sundry, have in caution's innermost room a confidant, a faithful mirror, whose correction you value when disillusionment is necessary.”

“The truths that matter most to us come always half spoken.”

“Above all, don't lie to yourself. The man who lies to himself and listens to his own lie comes to a point that he cannot distinguish the truth within him, or around him, and so loses all respect fo...”

“Of all the bright cruel lies they tell you, the cruelest is the one called love.”

“Don't cry, I'm sorry to have deceived you so much, but that's how life is.”

“The truth." Dumbledore sighed. "It is a beautiful and terrible thing, and should therefore be treated with great caution.”

“The truth is rarely pure and never simple.”

“Never tell the truth to people who are not worthy of it.”