Zoey Kruger: You gonna rape and kill me?
Dexter: What is it with you and rape? No one's raping anyone. Killing on the other hand...

[After Rita demands to know what's inside Dexter's "tools" suitcase, which is revealed to be a gun]
Dexter: It was Harry's. I wasn't comfortable having it now with the kids, so I kept it here.
Dexter: See? I have nothing to hide ...
Dexter: [voiceover] ... except for the syringes, scalpels and bonesaws hidden in that secret drawer underneath.

[Arthur Mitchell wakes up in Dexter's kill room, seemingly shocked by his surroundings]
Dexter: Guess you were picturing a different scenario.
Arthur: I was following my path.
Dexter: So was I.
Arthur: God led you to me.
Dexter: Hardly.
[Dexter cuts Arthur's cheek and creates a blood slide trophy; Arthur groans in pain]
Arthur: Is this who you are?
Dexter: Ta-da!
Arthur: Look at you! I never took pride in what I did!
Dexter: No, you were a very special kind of monster. You destroyed your own family.
Arthur: I gave them everything!
Dexter: No, you took everything; their future, their diginity, their hope... Christine even killed herself...
Arthur: No!
Dexter: ...because of you.
Arthur: She was weak!
Dexter: I can't believe there was a time when I actually thought I could learn something from you.
Arthur: You think you're better than I am?
Dexter: No. But I want to be.
Arthur: You can't control the demon inside of you any more than I could control mine.
Dexter: Did you ever actually try?
Arthur: Oh, God yes. I prayed to be changed, to be made different.
Dexter: That's not trying, that's waiting to be stopped.
Arthur: It worked, didn't it?
[They both look around at the kill room]
Arthur: Case in point.
Dexter: So what's the alternative, Arthur? Leave? Disappear? Fake my own death and start over again?
Arthur: No. You'll still be you.
Dexter: I have a family too, Arthur. And I'm good for them.
Arthur: [Laughs] You're like a child.
Dexter: A child with a big knife.
Arthur: You dream of a heaven you'll never see.
Dexter: I don't believe in heaven.
Arthur: Oh, but you do! This isn't your doing. This is God's plan. I accept that now. You have to do the same.
Dexter: I accept nothing. Nothing is inevitable.
Arthur: It's already over.
[Dexter looks confused and somewhat taken aback]
Arthur: It's already over. [Looks at the toy train set in the room] Could you...?
[Dexter turns on the train set and record player]
Arthur: Thank you. [singing] "I'll give her all the love I have to give, as long as we both shall live..."
[Dexter puts on his headgear and picks up a framing hammer, which he holds over Arthur]
Dexter: Now it's over.
[He flips the hammer so the sharp points are now facing down, then swings it towards Arthur.]

[Dexter has just discovered Rita's dead body, with Harrison lying in a pool of her blood]
Dexter: [voiceover] Born in blood. Both of us. Harry was right. I thought I could change what I am, keep my family safe. But it doesn't matter what I do, what I choose... I'm what's wrong. This is fate.
Season 5

[Dexter is about to kill Zoey Kruger, a police officer who murdered her family]
Zoey Kruger: You can't hide what you are.
Dexter: Oh, I can. I'm better at it than you.
Zoey Kruger: You will choose your life over theirs.
Dexter: I won't. I'd rather risk with them knowing the truth ... [Dexter stops talking, thinking] than losing them. [emotionally] I don't want to lose them. I don't.