No Matter How Powerful You Become, Don't Try To Shoulder Everything Alone. If You Do, You Will Surely Fail.
Related in Uchiha Itachi's best quotes in Naruto.
You Just Don't Have Enough...No, You Lack It Completely...The Greed, For Human Life.
Forgive Me Sasuke, Some Other Time, Okay?
Why Do You Care So Much About My Little Brother?
You Are Weak. And You Are Weak Because You Don't Have Enough Hate.
I Have Given You Some Of My Powers. Though I Hope That The Day You Will Have To Use Them Never Comes.