I recognize it!
It's Legolas on Caradhras when he comes back from reconnoitering:
"Well," cried Legolas as he ran up, "I have not brought the Sun. She is walking in the blue fields of the South, and a little wreath of snow on this Redhorn hillock troubles her not at all. But I have brought back a gleam of good hope for those who are doomed to go on feet."