Answer
Quotation 1: "Even in this gloom hope gleams again. ... The accursed darkness itself has been a cloak to us." - It is important to carry on even in the face of obstacles.
Quotation 2: "It is not our part to master all the tides of the world, but to do what is in us . . . uprooting the evil in the fields that we know." - Help can come from unexpected places.
Quotation 3: "I'll get there, if I leave everything but my bones behind," said Sam. "And I'll carry Mr. Frodo up myself, if it breaks my back and heart." - Solve the problem in front of you.