"Final Words" (最後の言葉, Saigo no Kotoba) is chapter 402 of the original Naruto manga.
Sasuke remembers his childhood with Itachi, who was a loving older brother. Sasuke idolised Itachi's talent and pleaded for Itachi to teach him something, but Itachi would always refuse by poking him on the head and promising to do so some other time. Thinking about his most recent encounter with Itachi, before Itachi died, Sasuke remembers Itachi's final action. Rather than take Sasuke's eyes, Itachi poked him on the head and apologised for no longer being able to fulfil the promise of "some other time". Accepting that his brother was a good person, Sasuke, Mangekyō Sharingan active, informs Hebi, now renamed Taka, that their new mission is to destroy Konoha.