It can be found in the Quincy police station, inside the terminal near the entrance.
Baker: Look Tessa, the orders come down straight from Captain Wes. Clint has the command here and that's just how it is.
If you keep running your mouth off, he's going to make an example of you to show that he's still in charge. Why do you think he picked you to deal with those scorps down at Super Duper Mart?
Maybe you got away with that shit back when you were running with raiders, but Gunners stick to the chain of command. Besides, we wouldn't have been able to take Quincy without him, and you wouldn't have that sweet power armor, so get over it.