Supernatural, Season 9

Castiel:
Dean. If the angel possessing Sam isn't Ezekiel, then who is it?

Dean:
A dead man walking.

Castiel:
What, you're gonna destroy him?

Dean:
Damn right.

Castiel:
You kill an angel, its vessel dies, too.

Dean:
Think I don't know that? If I don't end Sam and that halo burns him out and I... God, I was so damn stupid.

Castiel:
You were stupid for the right reasons.

Dean:
Yeah, like that matters.

Castiel:
It does. Sometimes that's all that matters.