Patronus Quotes

The Patronus is a kind of positive force, a projection of the very things that the dementor feeds upon - hope, happiness, the desire to survive - but it cannot feel despair, as real humans can, so the dementors can't hurt it. ~ J.K. Rowling

SCORPIUS: A doe? Lily's Patronus. SNAPE: Strange, isn't it? What comes from within. ~ J.K. Rowling

Prongs rode again last night ... You know, Harry, in a way, you did see your father last night ... You found him inside yourself. ~ J.K. Rowling

You see!" said a strained voice. Tonks was glaring at Lupin. "She still wants to marry him, even though he's been bitten! She doesn't care!"
"It's different," said Lupin, barely moving his lips and looking suddenly tense. "Bill will not be a full werewolf. The cases are completely-"
"But I don't care either, I don't care!" said Tonks, seizing the front of Lupin's robes and shaking them. "I've told you a million times...."
And the meaning of Tonk's Patronus and her mouse-colored hair, and the reason she had come running to find Dumbledore when she had heard a rumor someone had been attacked by Greyback, all suddenly became clear to Harry; it had not been Sirius that Tonks had fallen in love with after all.
"And I've told you a million times," said Lupin, refusing to meet her eyes, staring at the floor, "that I am too old for you, too poor....too dangerous...."
"I've said all along you're taking a ridiculous line on this, Remus," said Mrs. Weasley over Fleur's shoulder as she patted her on the back.
"I am not being ridiculous," said Lupin steadily. "Tonks deserves somebody young and whole."
"But she wants you," said Mr. Weasley, with a small smile. "And after all, Remus, young and whole men do not necessarily remain so."
He gestured sadly at his son, lying between them.
"This is....not the moment to discuss it," said Lupin, avoiding everybody's eyes as he looked around distractedly. "Dumbledore is dead...."
"Dumbledore wo ~ J.K. Rowling

There's something in science like the shine of the Patronus Charm, driving back all sorts of darkness and madness ... ~ Eliezer Yudkowsky

I heard from my dear friend Tiberius Ogden, that you can produce a Patronus? For a bonus point ... ?
Harry raised his wand, looked directly at Umbridge, and imagined her being sacked.
Expecto Patronum!
The silver stag erupted from the end of his wand and cantered the length of the hall. ~ J.K. Rowling

Not an exact quote, more like an opinion, a thought. Dementors suck out happiness from people. The make people remember their worst moments in life. The way to defeat them / repel them is to cast a patronus charm, [incantation: expecto patronum. If my latin serves me right it means "I expect / I command my patron].
The difficulty lies in casting the charm while those foul creatures make you feel terrible and the charm only works if you can conjure up a most happy memory.
I suggest a new / additional interpretation of JK Rowling's idea:
Demen - tors are your inner demons that make you feel terrible, things you did in your life, terrible losses you experienced (Harry hears his mother's screams) and negative emotions.
Those inner demons TORment you and your soul. You can only escape those horrible impressions with an overwhelming positive force of imagination. Happy moments in your life, thoughts about friends, family, love and connection versus the horrible loneliness that your inner demons create. ~ ThomThor

Well, when it works correctly, it conjures up a Patronus," said Lupin, "which is a kind of anti-dementor - a guardian that acts as a shield between you and the dementor. ~ J.K. Rowling

Harry flung himself out from behind the bush and pulled out his wand.

"EXPECTO PATRONUM!" he yelled.

And out of the end of his wand burst, not a shapeless cloud of mist, but a blinding, dazzling, silver animal. He screwed up his eyes, trying to see what it was. It looked like a horse. It was galloping silently away from him, across the black surface of the lake. He saw it lower its head and charge at the swarming dementors. . . . Now it was galloping around and around the black shapes on the ground, and the dementors were falling back, scattering, retreating into the darkness. . . . They were gone.

The Patronus turned. It was cantering back toward Harry across the still surface of the water. It wasn't a horse. It wasn't a unicorn, either. It was a stag. It was shining brightly as the moon above. . . it was coming back to him. . . .

It stopped on the bank. Its hooves made no mark on the soft ground as it stared at Harry with its large, silver eyes. Slowly, it bowed its antlered head. And Harry realized. . . "Prongs," he whispered.

But as his trembling fingertips stretched toward the creature, it vanished. ~ J.K. Rowling

That raccoon is my goddamn role model. He is the worst and best Patronus ever, and I want to be just like him when I grow up. ~ Jenny Lawson

Been trying to keep an eye out for you."
Ron gasped.
"The silver doe!" he said excitedly. "Was that you too?"
"What are you talking about?" said Aberforth.
"Someone sent a doe Patronus to us!"
"Brains like that, you could be a Death Eater, son. Haven't I just proved my Patronus is a goat?"
"Oh," said Ron. "Yeah…well, I'm hungry!" he added defensively as his stomach gave an enormous rumble. ~ J.K. Rowling

From what the Headmaster told me this morning, you saved a lot of lives last night, Harry. If I'm proud of anything, it's how much you've learned. Tell me about your Patronus."
"How d'you know about that?" said Harry, distracted.
"What else could have driven the Dementors back?"
Harry told Lupin what had happened. When he'd finished, Lupin was smiling again.
"Yes, your father was always a stag when he transformed," he said. "You guessed right... that's why we called him Prongs. ~ J.K. Rowling

This is in fact a sly test disguised as an interesting point of conversation. If he doesn't know what a patronus is, I know immediately that there's very little point in proceeding with the bench-based festivities. ~ Laura Steven