Clerk: [Homer grabs for his gun, but the cashier holds onto it] Sorry, the law requires a five-day waiting period. We've got to run a background check. Homer: Five days? But I'm mad now! [the cashier pulls the gun away from him] Homer: I'd kill you if I had my gun. Clerk: Yeah, well, you don't.
This quote occurs at 00:06:32-00:06:47 in the video.