Piping down the valleys wild,
Piping songs of pleasant glee,
On a cloud I saw a child,
And he laughing said to me:

'Pipe a song about a Lamb!'
So I piped with merry cheer.
'Piper, pipe that song again;'
So I piped: he wept to hear.

'Drop thy pipe, thy happy pipe;
Sing thy songs of happy cheer:!'
So I sang the same again,
While he wept with joy to hear.

'Piper, sit thee down and write
In a book, that all may read.'
So he vanish'd from my sight;
And I pluck'd a hollow reed,

And I made a rural pen,
And I stain'd the water clear,
And I wrote my happy songs
Every child may joy to hear.

William Blake

http://www.poemhunter.com/poem/introduction-to-the-songs-of-innocence/