Isn �t it more important that it may change the way they feel about themselves??
 
I suggest googling "motivational quotes" and see what you can come up with. 
I simply copied some from the first site I clicked on:
 
"I �m not telling you it is going to be easy - I �m telling you it �s going to be worth it" 
-- Art Williams
"The most painful thing to experience is not defeat but regret" 
-- Leo Bascaglia
"The greatest mistake you can make in life is to be continually fearing you will make one." 
-- Elbert Hubbard
 
These quotes I gave -printed on a bookmark- to my students last year: 
 
"Excellence is not a skill, it is an attitude"   Ralph Marston 
"No-one knows what he can do until he tries"   Publilius Syrus
 
and since there was a spelling mistake in one of them (which I noticed only after handing them out) I made a new bookmark which read:
 
"Learn from the mistakes of others, you can never live long enough to make them all yourself"  John Luther