So then, altogether it would be:
用力力中能藉力, 临机机内要关机
"In the use of force, from within the force, you are able to borrow force; as you encounter a movement's power, from inside of the movement's power, you must cut off the movement's power."
This 14-character couplet explains the two main principles forming the basis of
Lin Siu Daai Da (连消带打) technique.
Very nice, Sifu Derek Johnson!