'It was wrong to do this,' said the angel.
'You should live like a flower,
Holding malice like a puppy,
Waging war like a lambkin.'

'Not so,' quoth the man
Who had no fear of spirits;
'It is only wrong for angels
Who can live like the flowers,
Holding malice like the puppies,
Waging war like the lambkins.'

Stephen Crane

http://www.poemhunter.com/poem/it-was-wrong-to-do-this-said-the-angel-2/