The Reincarnation of the Avatar
Avatar Kuruk: I lost the woman I loved, to Koh, the Face Stealer. It was my fault. If I had been more attentive and more active, I could have saved her. Aang, you must actively shape your own destiny and the destiny of the world.
Avatar Kyoshi: Personally, I don’t really see the difference, but I assure you, I would have done whatever it took to stop Chin. I offer you this wisdom, Aang. Only justice will bring peace.
Avatar Roku: If I had been more decisive, and acted sooner, I could have stopped Sozin, and stopped the war before it started. I offer you this wisdom, Aang. You must be decisive.
Avatar Yangchen: Here is my wisdom for you: selfless duty calls for you to sacrifice your own spiritual needs and do whatever it takes to protect the world.
(via Avatar Wiki)