Not for the sake of the gold, 
Not for the sake of the fame, 
Not for the prize would I hold 
Any ambition or aim: 
I would be brave and be true 
Just for the good I can do. 
 
I would be useful on earth, 
Serving some purpose or cause, 
Doing some labor of worth, 
Giving no thought to applause. 
Thinking less of the gold or the fame 
Than the joy and the thrill of the game. 
 
Medals their brightness may lose, 
Fame be forgotten or fade, 
Any reward we may choose 
Leaves the account still unpaid. 
But little real happiness lies 
In fighting alone for a prize. 
 
Give me the thrill of the task, 
The joy of the battle and strife, 
Of being of use, and I'll ask 
No greater reward from this life. 
Better than fame or applause 
Is striving to further a cause.
Edgar Albert Guest
http://www.poemhunter.com/poem/purpose-60/