There was a mystical poet, deeply devoted to Shiva, who had composed a hymn in Shiva's name.
"What a marvelous hymn I have composed!" he thought to himself.
Then Shiva's faithful white bull Nandi appeared to the poet in a dream. The bull opened his mouth, revealing his teeth, and there, written on each tooth, were the words to the hymn.
The poet realized that he had composed nothing. The words were not his but had come to him from the past that has no beginning.
Thereafter when he sang the hymn, he thought only of Shiva, not of himself.
Inspired by: Tales and Parables of Sri Ramakrishna
Notes: This is story 52 in the book. You can read more about the bull Nandi at Wikipedia. This story reminds me of the fable about Hanuman and how Rama's name was written on his very bones.