“He can, who thinks he can”

If you think you are beaten, you are,
 If you think you dare not, you don't,
If you'd like to win, but think you can't,
 It's almost a cinch you won't.
If you think you'll lose, you're lost,
 For out in the world we find,
Success begins with a fellow's will -
 It's all in the state of mind.
If you think you're outclassed, you are,
 You've got to think high to rise.
You've got to be sure of yourself before
 You can ever win a prize.
Life's battles don't always go
to the stronger or faster man,
but soon or late  the man who wins
Is the man WHO THINKS HE CAN.

                                   - Unknown 

The best line of the poem which I liked is “stronger or faster man don’t win the life’s battle but the man who thinks he can win”.