Robert Graves - Hate Not - Fear Not

Kill if you must, but never hate:
Man is but grass and hate is blight,
The sun will scorch you soon or late,
Die wholesome then, since you must fight.

Hate is a fear, and fear is rot
That cankers root and fruit alike,
Fight cleanly then, hate not, fear not,
Strike with no madness when you strike.

Fever and fear distract the world,
But calm be you though madmen shout,
Through blazing fires of battle hurled,
Hate not, strike, fear not, stare Death out!

Robert Graves

http://www.poemhunter.com/poem/hate-not-fear-not/