"Power to Believe" (信じる力, Shinjiru Chikara) is episode 158 of the Naruto: Shippūden anime.
Konan and the Six Paths of Pain continue their attack on Konohagakure while systematically interrogating and killing shinobi and civilians alike regarding the whereabouts of Naruto Uzumaki, the jinchūriki of the Nine-Tailed Fox. Due to Tsunade's duties as Hokage and Shizune leading the autopsy, Sakura is placed in charge of all the wounded at the Konoha Hospital. Danzō Shimura decides to alert Koharu Utatane and Homura Mitokado, the two elders of the Konoha Council, that Pain of the Akatsuki is destroying their village in an attempt to find Naruto, whom Tsunade is attempting to bring back to the village at the very moment.
Angered, the two elders storm into Tsunade's office, asking her to leave Naruto at Mount Myōboku, unsatisfied with her handling of events. As the elders mention the dangers of handing the Nine-Tails over to Pain, who had killed Jiraiya of all people, Tsunade is vexed as they refer to Naruto as merely the vessel of the tailed beast. Pulling them off their feet by their collars, she announces that Naruto is not just a vessel, but a shinobi of Konoha, a comrade, who has sworn to defend their village, recalling when Naruto saved her during her battle with Kabuto; she proceeds to tell the elders that the Third Hokage, Chiyo of Suna and Jiraiya all possessed something that the two of them lack — the power to believe, to have faith, in someone like Naruto. Back at Mount Myōboku, Naruto has perfected becoming one with nature and proceeds to use his Sage Mode to hone a certain technique.
Shizune rushes in to Tsunade's office, revealing that they found chakra receivers within the body Jiraiya procured, and that the very chakra receiver is still working. Musing why Pain is sending chakra to the other bodies, Tsunade orders Kōsuke, a messenger toad, to return to Mount Myōboku and relay the situation to Naruto and Fukasaku; Tsunade then proceeds to head to the roof. As everyone clears out of the office, Kōsuke prepares to dispel himself back home, only to be stabbed and killed by Danzō, who does not want the Nine-Tails to return to Konoha. On the roof, Tsunade summons Katsuyu and tells her to use her Slug Great Division to split into numerous, smaller slugs and heal the wounded, swearing to protect the village as Hokage. Meanwhile, Pain's Deva Path interrogates Iruka, who does not divulge Naruto's location. Before Pain can kill Iruka, he is saved by Kakashi, who prepares to deal with the Deva Path himself while Iruka escapes.