5x01 Sympathy for the Devil

Zachariah: What, you thought you could actually kill Lucifer? You simpering wad of insecurity and self-loathing? No. You're just a human, Dean. And not much one of them.
Dean Winchester: What do you mean, I'm the sword?
Zachariah: Michael's weapon. Or, rather, his... receptacle.
Dean Winchester: I'm a vessel?
Zachariah: You're "the" vessel. Michael's vessel.
Dean Winchester: How? Why? Why me?
Zachariah: Because you're chosen! It's a great honor, Dean.
Dean Winchester: Oh, yeah. Yeah, life as an Angel condom. That's real fun!

Zachariah: How are you...?
Castiel: Alive? It's a good question. [indicating Dean and Sam] How did these two end up on that airplane? Another good question, because the angels didn't do it. I think we both know the answer, don't we?
Zachariah: No... It's not possible.
Castiel: [fiercely] It scares you. Well, it should. Now, put these boys back together, and go. I won't ask twice. [Zachariah disappears; the brothers recover] You two need to be more careful.
Dean Winchester: Yeah, starting to get that. Your frat brothers are bigger dicks than I thought.
Castiel: I don't mean the angels. Lucifer is circling his vessel, and once he takes it those hex bags won't be enough to protect you. [he touches their chests, the brothers flinch and groan]
Dean Winchester: What the hell was that?
Castiel: An Enochian sigil. It'll hide you from every angel in creation. Including Lucifer.
Dean Winchester: What, did you just brand us with it?
Castiel: No, I carved it into your ribs. [pause while they take this in]
Sam Winchester: Hey Cas, were you really dead? [a beat]
Castiel: Yes.
Dean Winchester: Then how are you back? [Castiel looks at them for a moment, not answering, then vanishes with a sound of wingbeats]

Dean Winchester: [angrily] You listen to me, you two-faced douche. After what you did, I don't want jack-squat from you!
Zachariah: You listen to *me*, boy. You think you can rebel against us? As Lucifer did?

Zachariah: You're bleeding...
Dean Winchester: [looks down] Oh yeah. A little insurance policy in case you dicks showed up.

Zachariah: [lurching forward] No...!

Dean Winchester: [to the empty air] Learned that from my friend Cas, you sonofabitch.