Hope

"There, peeping among the cloud-wrack above a dark tower high up in the mountains, Sam saw a white star twinkle for a while. The beauty of it 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."
J. R. R. Tolkien, Lord of the Rings

What did hope do for Sam? It reminded him that the Shadow was only a small and passing thing. You must cling to your hope regardless of how dark it appears around you, look at Christ's promise that he is returning to this earth and he will take you to his Father's house where a place has been prepared for you. The reason the Shadow is only a small and passing thing is because there is a light and a high beauty forever beyond the reach of the darkness.