Castiel and Crowley in “Unfinished Business”

Castiel

If you touch the Winchesters...

Crowley

Please. I heard you the first time. I promise -- nary a hair on their artfully tousled heads. Besides, I think they've proven my point for me. It's always your friends, isn't it, in the end? We try to change. We try to improve ourselves. It's always our friends who got to claw into our sides and-and hold us back. But you know what I see here? The new God [pointing at Castiel] and the new Devil, working together.

Castiel

Enough! You stop talking and get out of my sight.

Crowley

Well... Glad I came. You're welcome, by the way. You know the difference between you and me? I know what I am. What are you, Castiel? What exactly are you willing to do?