I stumbled upon this poem and I love its message. Strength is a state of mind perhaps more than anything else. You have to believe in yourself and know that you are strong before you actually are.
(The poem is gender bias, therefore if you are female think
The Woman Who Thinks She Can!)

The Man 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 that you wont.

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 win the prize.

Life's battles don't always go
To the strongest or fastest man;
But sooner or later the man who wins
Is the man who thinks he can!

Author ~ Walter D. Wintle