| Quote #1
The maid servant recognized Jude, and whispered her surprise to her mistress […] that the student, 'who kept hisself so particular,' should have suddenly descended so low as to keep company with Arabella. (1.7.21)
Here's that whole living-in-two-worlds thing: even when he is still in Marygreen, Jude is seen as someone different from many people in the town.
| Quote #2
Only a wall—but what a wall! (2.2.13)
This is kind of Jude's life in Christminster in a nutshell. He's just separated from the college by a wall, but in reality that wall is class, money, and standing that he can never climb. Not even if he had an awesome jetpack (do not try this at home!).
| Quote #3
How could one of his cross-grained, unfortunate, almost accursed stock, have contrived to reach this pitch of niceness? (1.2.30)
This brilliant little sentence demonstrates what Jude thinks about himself and where he comes from (he's the "unfortunate, almost cursed stock" in question). It also establishes that Sue, despite coming from the same place, is something entirely different in Jude's eyes.