Courage is the most important of the virtues, because without courage, you can’t practice any of the other virtues consistently. You can practice virtue erratically, but nothing consistently without courage.
~Maya Angelou
http://en.wikiquote.org/wiki/Maya_Angelou
 
Start by doing what’s necessary; then do what’s possible; and suddenly you are doing the impossible.
St. Francis of Assisi (attributed)
http://en.wikiquote.org/wiki/St._Francis_of_Assisi