There are several examples of justice being delivered in Ray Bradbury's Fahrenheit 451. The first takes place with the death of Beatty.
Montag's boss, Beatty, has been harassing Montag for some time. He later admits to knowing that Montag has books in his possession. But Beatty is something of a contradiction: for a man who burns books, he knows a tremendous amount about them and can quote them perfectly, inferring that he is a reader himself. If this is the case, he is driven to destroy the things that he also loves, even if he doesn't admit it. There is a suggestion when Montag and Beatty confront one another for the last time that Beatty welcomes his death: almost like "suicide by fireman."
Beatty has just burned down Montag's house: Mildred turned Montag in for owning books. Beatty hits Montag and the green bullet he has in his ear as he listens to Faber, falls onto the ground. Beatty picks it up and realizes that Montag is involved with another law-breaker. He threatens to hunt Faber down later. It is at this point that Montag rebels.
"No!" said Montag.
He switched the safety catch on the flamethrower. Beatty glanced instantly at Montag's fingers and his eyes widened the faintest bit.
It seems that till now, Beatty has thought he has Montag all figured out. However, with Montag's movement with the flamethrower, even Beatty has found something left in the world to surprise him. I think it's been a long time since this has happened to him.
Beatty grinned his most charming grin. "Well, that's one way to get an audience. Hold a gun on a man and force him to listen to your speech.
Beatty starts to push Montag to act. It is here that his desire to die seems evident as he drives Montag kill him.
Why don't you belch Shakespeare at me, you fumbling snob?
He then begins to quote Julius Caesar, word-for-word, from Act Four, scene three, lines 73-76, as Brutus defies Cassius' threats.
Go ahead now, you second-hand litterateur, pull the trigger.
He moves toward Montag who, in fact, does pull the trigger, which stops Beatty verbal abuse and violently takes his life. While there is a certain amount of justice in this, it is also painfully sad. Beatty was very smart, but he seemed unable to live out the truth of his own convictions, and Bradbury passes judgment here on him as well.
We see justice again when Montag destroys the Mechanical Hound who has also been harassing him, growling at him with menacing intent:
Montag caught it with a bloom of fire, a single wondrous blossom that curled in petals of yellow and blue and orange about the metal dog, clad it in a new covering...
Finally, there is also justice delivered to the city as the bombers come and destroy it. Faber had predicted this when he told Montag to be patient with others who he had been so like until recently:
They are so confident that they will run on forever. But they won't run on. They don't know that this is all one huge big blazing meteor that makes a pretty fire in space, but that someday it'll have to hit. They see only the blaze, the pretty fire, as you saw it.
As Montag makes his escape from the Mechanical Hound, from the police after killing Beatty, he witnesses the destruction of the city. With others like himself, he will join even more crusaders for books that will recall, memorize, the content of the books they have read, with a hope to rebuild society. Judgment is passed on society, and justice is served as it is destroyed.