Anyone who wishes to learn it must devote its life to and must start as a child, preferably at the age of eight.
9 seconds sound clip from the Born Invincible (1978) movie soundboard.
You can hear this line at 00:00:32 in the DVD version of the movie.
Quote context
[...]
- All the many kung-fu styles are being developed in various parts of China...
- The one recognized as being the most difficult and the most deadly is the Tai Chi technique.
- It must bathe in the secret lotions, take the special pills and hold to a rigorous diet for 30 years
- The Earth's fundamental forces are tapped via the eight octograms.
- The whole body is in balance.
- A change in emphasis in one part of the body will affect a comforting change in another part.
[...]