Here's why:
* Shared Occupation: Both Arthur and Moody worked at the Ministry of Magic. Arthur was in the Misuse of Muggle Artefacts Office, while Moody was an Auror (an elite wizarding law enforcement officer).
* Mutual Respect: While their personalities and approaches to wizarding life differed, both Arthur and Moody were dedicated public servants. They likely respected each other's skills and commitment to protecting the wizarding world.
* Collaboration: Though their roles were distinct, there were opportunities for them to collaborate. For example, Arthur might have been consulted about Muggle objects used in Auror investigations.
* No Evidence of Conflict: Throughout the books, there's no indication of any animosity or conflict between the two characters.
It's important to note that Moody was a gruff and intimidating character, and he wasn't always easy to get along with. However, this doesn't necessarily imply an adversarial relationship with Arthur.