Be the change you wish to see in the world. Did you know that nowhere in Gandhi's writings can these exact worlds in this order be found. The actual quote from where this saying came from is thought to be: "If we could change ourselves, the tendencies in the world would also change. As a man changes his own nature, so does the attitude of the world change towards him. ... We need not wait to see what others do."
Either way this saying is very meaningful and popular.