Professor Snape: Potter, what are y

Professor Snape: Potter, what are you doing wandering the corridors at night?
Harry: Nothing... I was sleepwalking.
Professor Snape: How extraordinarily like your father you are Potter, he too was exceedingly arrogant, strutting about the castle.
Harry: My Dad didn't strut, and nor do I. Now, if you don't mind, I'd appreciate it if you could lower your wand. (Harry Potter and The Prisoner of Azkaban)
Severus Snape: It appears there is a connection between the Dark Lord's mind and your own. Whether he is, as yet, aware of this connection is for the moment unclear. Pray he remains ignorant.
Harry Potter: You mean if he knows about it then, he'll be able to read my mind.
Severus Snape: Read it, control it, unhinge it. In the past it was often the Dark Lord's pleasure to invade the minds of his victims, creating visions designed to torture them into madness. Only after extracting the last exquisite ounce of agony, only when he had them litterly begging for death would he finally... kill them. Used properly, the power of Occlumency will help shield you from access or influence. In these lessons I will attempt to penetrate your mind. You will attempt to resist. Prepare yourself! Legillimens!(Harry Potter and The Order Of The Phoenix)
Severus Snape: You're just like your father. Lazy, arrogant...
Harry Potter: Don't say a word against my father!
Severus Snape: - Weak.
Harry Potter: I'm not weak!
Severus Snape: Then prove it! (Harry Potter and The Order Of The Phoenix)
Professor Severus Snape: No! Don't kill me!
Professor Albus Dumbledore: The prophecy did not refer to a women. It spoke of a boy born at the end of July.
Professor Severus Snape: Yes but, he thinks its her son! He intends to hunt them down now, to kill them. Hide her, hide them all. I beg you.
Professor Albus Dumbledore: What will you give me in return, Severus?
Professor Severus Snape: Anything. (Harry Potter and Th Deathly Hallows part 2)
Professor Albus Dumbledore: We both know Lord Voldemort has ordered the Malfoy boy to murder me. But should he fail, I should presume the Dark Lord will turn to you. You must be the one to kill me, Severus. It is the only way. Only then will the Dark Lord trust you completely.
[Flashback of Snape killing Dumbledore]
Professor Albus Dumbledore: There will come a time when Harry Potter must be told something. But you must wait until Voldemort is at his most vulnerable.
Professor Severus Snape: Must be told what?
[Shot of Snape going through the halls of the Potter house]
Professor Albus Dumbledore: On the night Lord Voldemort went to Godric's Hollow to kill Harry, and Lily Potter passed herself between them, the curse rebounded. When that happened, a part of Voldemort's soul lached itself onto the only living thing it could find. Harry himself. There's a reason Harry can speak with snakes. There's a reason he can look into Lord Voldemort's mind. A part of Voldemort lives inside.
Professor Severus Snape: So when the time comes... the boy must die?
Professor Albus Dumbledore: Yes. Yes... he must die.
[Shot of Snape collapsing at the sight of Lily's dead body]
Professor Severus Snape: You've kept him alive so that he can die at the proper moment. You've been raising him like a pig for slaughter!
Professor Albus Dumbledore: Don't tell me now that you've grown to care for the boy.
[Snape casts a Patronus in the shape of a doe, just like Lily's- the same one that helped Harry find the Sword of Gryffendor in Part 1]
Professor Albus Dumbledore: Lily... after all this time?
[Shot of Snape holding Lily's body in his arms while crying]
Professor Severus Snape: Always. (Harry Potter and Th Deathly Hallows part 2)