"Thank You" (ありがとう, Arigatō) is chapter 504 of the original Naruto manga.
Kushina protests the use of the Dead Demon Consuming Seal, asking Minato why he is sacrificing himself so she can meet Naruto for a few minutes when he's older. He convinces her that it's the right thing to do because "he could never substitute for her". The death god grabs the Nine-Tails but seals only half of it. Minato summons Gerotora and gives him the key to the seal he's about to put on Naruto. Kushina gives Naruto a long list of things to do then Minato performs the Eight Trigrams Sealing Style on Naruto. In the present, Kushina apologises to Naruto for not being there and he tells her he didn't know what a parent's love was like but he managed. Naruto thanks his parents for making him their son and tells them that his vessel is full of love from the both of them. As Kushina fades away, she thanks him for letting her and Minato be his parents and thanks him for being born to them.