Itachi: 
"Even the strongest of opponents always have a weakness" 
"Now I see it, people hate and fear what they don't understand. Pathetic" 
"It is foolish to fear what we've yet to see and know" 
"Everyone lives bound by their own knowledge and awareness. They define that as reality; but knowledge and awareness are vage, and perhaps better called illusions" 

Kakashi: 
"A ninja must see underneath the underneath" 
"They say that the nail that sticks up is the one that gets hammered down" 
"I never let my comrades die" 
"To abandon your duty is not courageous. Below the courageous, there is nothing. Those are the previous Hokage's words" 

Naruto: 
"I never give up. I never go back on my word. That is my way of the ninja!" 
"The pain of being lonely.. is out of this world, isn't it?" 
"Until I reach my dream, I refuse to die" 
"Nothing is wrong with crying when you're happy" 
"I'm going to prove that in this world, Heroes do exist!" 
"Real strength is not what you have when fighting for yourself. When you have something special that you want to protect, only then can you become truly strong" 
"If you don't like your destiny, don't accept it. Instead, have the courage to change it the way you want it to be" 
"Then I will break that curse. If there's such thing as peace, I will find it. I won't give up!" 
"I don't care who I have to fight... If he rips my arms off, I'll kick him to death. If he rips my legs off, I'll bite him to death. If he rips my head off, I'll stare him to death. And if he gouges my eyes, I'll curse him to death... Even if I'm torn to shreds... I will find a way to take Sasuke back!" 
"I will protect my friends!"