TRUTH is enough for prose:
Calmly it goes
To tell just what it knows.

For verse, skill will suffice-
Delicate, nice
Casting of verbal dice.

Poetry, men attain
By subtler pain
More flagrant in the brain-

An honesty unfeigned,
A heart unchained,
A madness well restrained.

Christopher Morley

http://www.poemhunter.com/poem/at-the-mermaid-caffeteria/