"It is not a joke. It is bullying plain and simple. I won't be party to it." Money through unethical means was one thing, but this--! Also he doesn't like the demon's tone.

He draws himself up to his full five foot ten inches, looking at the demon down his nose no matter the height difference, flaring his wings a little.

"I am an Angel of the Almighty and I won't be threatened. We are enemies and we will be enemies, even to extinction."

Though he would rather not do this. It's going down a path he can't easily back down from. If only Crowley were here, he'd find some way out of this, but it is just Aziraphale alone in this unpleasant place. But he will be resolute! Even if he's meant to pay for it.