No one is beat till he quits,
No one is through till he stops,
No matter how hard Failure hits,
No matter how often he drops,
A fellow's not down till he lies
In the dust and refuses to rise

Fate can slam him and bang him around.
And batter his frame till he's sore,
But she never can say that he's downed
While he bobs up serenely for more.
A fellow's not dead till he dies,
Nor beat till no longer he tries.

Edgar Albert Guest

http://www.poemhunter.com/poem/defeat-39/