"Well - of course," says Aziraphale with a concerned frown. "It's a standing offer. There's no... catch or anything like that." 'Monkey's Paw', good grief. He'd be insulted if it was remotely worth it. "I only want to help. It's what I do."

He's not about to push, that wouldn't be very angelic after all, but he's still feeling stung about being useless against the Devil, he has to offer something.