"Cross-Examination" (詰問, Kitsumon) is chapter 538 of the original Naruto manga.
As Naruto and B head towards the battle field, with Naruto in Nine-Tails Chakra Mode, the Nine-Tailed Demon Fox tells him that he is squandering its chakra like that. Naruto and the Fox have a conversation and the Fox tells him to stop being naive as there was no way he could shoulder the hatred of an entire war and Sasuke. After a flashback of Naruto and Sasuke while in the academy, Naruto walks into the Nine-Tails' cage and brings down the torii which pins the Nine-Tails down. Naruto then stares dead into the beast's eye and brimming with confidence tells him that he will do something about the war and Sasuke.