Most 'powerful' lines of Ea....

[Ibrîniðilpathânezel]

For myself, I have always been quite moved by Gandalf's remark to Frodo concerning life, death, and pity. And I have also been moved by his comments:

"Yet it is not our part to master all the tides of the world, but to do what is in us for the succour of those years wherein we are set; uprooting the evil in the fields that we know, so that those who live after may have clean earth to till. What weather they shall have is not ours to rule."

"We must walk open-eyed into that trap, with courage, but small hope for ourselves. For, my lords, it may well prove that we ourselves shall perish utterly in the black battle far from the living lands; so that even if Barad-dûr be thrown down, we shall not live to see a new age. But this, I deem, is our duty. And better so than to perish nonetheless -- as we surely shall, if we sit here -- and know as we die that no new age shall be."

And in the Silmarillion, for me it has to be Ilúvatar's statement:

"And thou, Melkor, shalt see that no theme may be played that hath not its uttermost source in me, nor can any alter the music in my despite. For he that attempteth this shall prove but mine instrument in the devising of things more wonderful, which he himself hath not imagined."

[Alcuin]

After the Battle of Azanulbizar, Thráin, who had lost an eye during the battle, proclaimed to the combined armies of the Seven Houses of the Dwarves, “Good! We have the victory. Khazad-dûm is ours!” The Dwarves replied,

Durin’s Heir you may be, but even with one eye you should see clearer. We fought this war for vengeance, and vengeance we have taken. But it is not sweet. If this is victory, then our hands are too small to hold it.