“I love the idea of what Crowley's idea of Aziraphale is. His idea is a lot more heroic and standing-up to everybody than Aziraphale's idea of Aziraphale.”
“Just as Aziraphale's idea of Crowley is somebody who can be flippant and insouciant when faced with the monsters of Hell”.
“They're probably each rather better at dealing with things than the other one is, but that's what they think the other one is probably like, and I love that”.
crowley used the metal tool in season 1 to start time, and we learn that he's used it first to start space. to create the stars -- he still remembers how. he still remembers all of heaven's passwords: in the book crowley is described as an optimist because he has the "utter surety... that the universe would look after him". not god, but the universe. and of course he does: he helped create it and he's looking after it, too.
think about it: aziraphale had a sword, but crowley is about to face satan who wants to destroy the world, and crowley's only weapon is a tool of creation