Madara:
"In this world, wherever there is light - there are also shadows. As long as the concept of winners exists, there must also be losers. The selfish desire of wanting to maintain peace causes wars, and hatred is born to protect love."
Itachi:
"We are humans, not fish. We don't know what kind of people we truly are until the moment before our deaths. As death comes to embrace you, you will realize what you are. That's what death is, don't you think?"
and
"I always lied to you telling you to forgive me. I used these hands to keep you at distance... I did not want you to get involved. But now... I think you could have changed father and mother. Perhaps even the entire Uchiha. If I would have stood in front of you and looked you in the eyes from the very beginning... talked to you instead of down to you... and been open about everything. But I failed, and speaking to you now, like this, isn't going to undo the permanent damage that's already been done to you. That's why I wanted to show you the truth. Even if it's just a little. And no matter what you decide to do from here on out, you never have to forgive me - I will always love you."
Hiruzen:
"To those who possess the Will of Fire, everyone is family. The desire to protect one's family builds thicker and stronger bonds between each and everyone in the village. If the Will of Fire is embraced by everyone, the village will be alright no matter what happens."
Sasuke's:
"If you think I'm just a foolish kid ruled by his emotions, that's fine. Following Itachi's path would have been too childish, the whispering of fools who don't know hatred. If anyone else tries to ridicule the way I live, I'll slaughter everyone they ever cared about. And then maybe they'll understand what it's like to taste... a little of my hatred."
(And some Peinful ones sometimes)