Bruce Lee was an American actor, film director, martial artist, philosopher and founder of the martial art Jeet Kune Do during 1940-1973.
His best known works are Tao of Jeet Kune Do, Fighting Method, The Art of Expressing the Human Body, and his commentaries on the Chinese martial arts.
In this quote, Bruce Lee says that simply pondering about a task is not enough. Making one concrete step must be taken for the furtherance and advancement of the goal.