Castiel and Dean in “Unfinished Business”

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.