There’s a powerful moment in J.R.R. Tolkien’s novel, The Return of the King, when Sam is encouraged by the light of a star. He’s engaged in a terrible mission against a dark enemy. They have very little hope of being successful. They don’t have enough food or water. They are deep in enemy territory, in constant threat of being discovered and destroyed. They’re exhausted, and yet and they trudge along, fighting against despair. They have to take turns sleeping, so that one can keep watch:

“Now you go to sleep first, Mr. Frodo,” he said. “It’s getting dark again. I reckon this day is nearly over.”

Frodo sighed and was asleep almost before the words were spoken. Sam struggled with his own weariness, and he took Frodo’s hand; and there he sat silent till deep night fell. Then at last, to keep himself awake, he crawled from the hiding-place and looked out. The land seemed full of creaking and cracking and sly noises, but there was no sound of voice or foot. Far above…in the West the night-sky was still dim and pale. There, peeping among the cloud-wrack above a dark tor high up in the mountains, Sam saw a white star twinkle for a while. The beauty smote his heart, as he looked up out of the forsaken land, and hope returned to him. For like a shaft, clear and cold, the thought pierced him that in the end the Shadow was only a small and passing thing: there was light and high beauty for ever beyond its reach….Now, for a moment, his own fate, and even his master’s ceased to trouble him. He crawled back into the brambles and laid himself by Frodo’s side, and putting away all fear he cast himself into a deep and untroubled sleep.

J.R.R. Tolkien, The Return of the King, 199.