WHO is it speaks of defeat? —
I tell you a Cause like ours
Is greater than defeat can know;
It is the power of powers!
As surely as the earth rolls round,
As surely as the glorious sun
Follows the great world moon-wave,
Must our Cause be won!
What is defeat to us? —
Learn what a skirmish tells,
While the great Army marches on
To storm earth's Hells!

Francis William Lauderdale Adams

http://www.poemhunter.com/poem/defeat-22/