Gandalf on Doing Our Part

"Yet it is not our part to master all the rides of our 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 whether they shall have is not ours to rule." - Gandalf (The Lord of the Rings: Return of the King, p. 160)