"Watch your thoughts, they become words.
Watch your words, they become actions.
Watch your actions, they become habits.
Watch your habits, they become character.
Watch your character, it becomes your destiny."
Variations of this are attributed to many people but the oldest variation is attributed to ancient Chinese philosopher Laotzi (see http://soniabranco.typepad.com/my_holistic_coach/2006/10/watch_your_thou.html )
