How we cite our quotes: (Book.Chapter.Paragraph)
Quote #1
We must nevertheless do him justice: malice was probably not innate in him. From his earliest interactions with men he had felt, and afterward he had seen himself, despised, rejected, cast off. Human speech had never been anything to him but a jeer or a curse. As he grew up he found nothing but hatred around him. He had adopted it. He had acquired the general malevolence. He had picked up the weapon with which he had been wounded. (IV.III.10)
You know that heart of gold you're always hearing about? That doesn't come until later. It's a lot easier for people to be nice when there is nothing really at stake. When Quasimodo is sympathetic toward Esmeralda, it takes on a special resonance because he doesn't usually roll that way.
Quote #2
It was a strange reversal for the poor fellow to be pilloried on the same spot where the preceding day he had been hailed and proclaimed Pope and Prince of Fools, escorted by the Duke of Egypt, the King of Thunes, and the Emperor of Galilee. (VI.IV.7)
If there's one thing this novel shows us, it's that crowds are fickle. The Festival of Fools is just about the only time that Quasimodo is accepted by society. The other 364 days of the year, it's back to business as usual (and "business as usual" here means hating on the poor bell-ringer). Since we first meet Quasimodo as he's being paraded around as the Pope of Fools, we're actually deceived into thinking that his life isn't all that bad. Then we see him fall. Hard.
Quote #3
This apparition, always so fatal to her, which had thrown her from misery to misery, roused her from her stupor. (VIII.IV.30)
Frollo has been dogging Esmeralda's every step. The other characters might be able to attribute their suffering to a lot of different things, but it seems pretty clear that Frollo is behind a lot of Esmeralda's misery. It makes Esmeralda's storyline all the more tragic, because we can imagine that if Frollo were only out of the picture, or a little less crazy, then maybe things would end well for her (unless she goes on loving Phœbus, that is). That's one thing that good tragedy does: it taunts you with the "if onlys."