“It is our choices, Harry, that show what we truly are, far more than our abilities.” –The Chamber of Secrets
“It matters not what someone is born, but what they grow to be.” –The Goblet of Fire
“The consequences of our actions are always so complicated, so diverse, that predicting the future is a very difficult business indeed.” –The Prisoner of Azkaban
“It does not do to dwell on dreams and forget to live.” –The Sorcerer’s Stone
“Fear of a name increases fear of the thing itself.” –The Sorcerer’s Stone
“There are all kinds of courage,” said Dumbledore, smiling. “It takes a great deal of bravery to stand up to our enemies, but just as much to stand up to our friends.” –The Sorcerer’s Stone
“People find it far easier to forgive others for being wrong than being right.” –The Half-Blood Prince
“We are only as strong as we are united, as weak as we are divided.” –The Goblet of Fire
“Differences of habit and language are nothing at all if our aims are identical and our hearts are open.” –The Goblet of Fire
“We cannot choose our fate, but we can choose others. Be careful in knowing that.” –The Order of the Phoenix
“It is important,” Dumbledore said, “to fight, and fight again, and keep fighting, for only then could evil be kept at bay, though never quite eradicated.” –The Half-Blood Prince
“The truth.” Dumbledore sighed. “It is a beautiful and terrible thing, and should therefore be treated with great caution.” –The Sorcerer’s Stone
“Curiosity is not a sin…but we should exercise caution with our curiosity.” –The Goblet of Fire
“Numbing the pain for a while will make it worse when you finally feel it.” –The Goblet of Fire
“Understanding is the first step to acceptance, and only with acceptance can there be recovery.” –The Goblet of Fire
“Youth cannot know how age thinks and feels, but old men are guilty if they forget what it was to be young.” –The Order of the Phoenix
“You think the dead we loved truly ever leave us? You think that we don’t recall them more clearly in times of great trouble?” –The Prisoner of Azkaban
“Do not pity the dead, Harry, pity the living, and above all those who live without love.” –The Deathly Hallows
“It is the unknown we fear when we look upon death and darkness, nothing more.” –The Half-Blood Prince
“Let us step into the night and pursue that flighty temptress, adventure.” –The Half-Blood Prince
“Ah, music,” he said wiping his eyes. “A magic beyond all we do here.” –The Sorcerer’s Stone
“Of course it is happening inside your head, Harry, but why on earth should that mean it is not real?” –The Deathly Hallows
“Words are, in my not so humble opinion, our most inexhaustible source of magic, capable of both influencing injury, and remedying it.” –The Deathly Hallows
BONUS: "Happiness can be found, even in the darkest of times, if only one remembers to turn on the light." –The Prisoner of Azkaban (from the screenplay, by Steven Kloves)