“The Elves may fear the Dark Lord, and they may fly before him, but never again will they listen to him or serve him. And here in Rivendell there live still some of his chief foes: the Elven-wise, lords of the Eldar from beyond the furthest seas. They do not fear the Ringwraiths, for those who have dwelt in the Blessed Realm live at once in both worlds, and against both the Seen and the Unseen they have great power.'

‘I thought that I saw a white figure that shone and did not grow dim like the others. Was that Glorfindel then?'

‘Yes, you saw him for a moment as he is upon the other side: one of the mighty of the Firstborn.’

— Gandalf and Frodo in J. R. R. Tolkien, The Fellowship of the Ring, 290