Trained in combat?" repeated Harry incredulously. "What does he think we're...

Trained in combat?" repeated Harry incredulously. "What does he think we're doing here, forming some sort of wizard army?"
"That's exactly what he thinks you're doing," said Sirius, "or rather, that's exactly what he's afraid of Dumbledore's doing -- forming his own private army, with which he will be able to take on the Ministry of Magic."
There was a pause in this, then Ron said, "That's the stupidest thing I've ever heard, including all the stuff that Luna Lovegood comes out with.