I love this by Martha Graham.
"I believe that we learn by practice. Whether it means to learn to dance by practicing dancing or to learn to live by practicing living, the principles are the same. In each, it is the performance of a dedicated precise set of acts, physical or intellectual, from which comes shape of achievement, a sense of one's being, a satisfaction of spirit. One becomes, in some area, an athlete of God. Practice means to perform, over and over again in the face of all obstacles, some act of vision, of faith, of desire. Practice is a means of inviting the perfection desired."
Here's what the dictionary says about her:
Graham, Martha (1893–1991), U.S. dancer, teacher, and choreographer. She evolved a new dance language using more flexible movements intended to express psychological complexities and emotional power.