Idiot…!! (馬鹿…!!, Baka…!!) is chapter 237 of the Naruto manga.
Although Sakura has said she will help him find Sasuke, Naruto is unwilling to wait for her and wants to try again as soon as he is better. Jiraiya visits him and offers to train him since Akatsuki won't be coming after him for another three years. Naruto declines, saying he needs to take Sasuke back from Orochimaru. Jiraiya tells him that Orochimaru won't be able to take Sasuke's body for another three years. He also suggests giving up on Sasuke, having previous experience with his own futile attempts to persuade Orochimaru to change his ways. Only a fool, he claims, would pass up years of training to save someone who doesn't want saving. Naruto says he would rather be a fool. Happy with this answer, Jiraiya leaves, telling Naruto that they will leave for his training as soon as he gets out of the hospital.