Chapter 7, Part 5B - Lieh Tzu

The second son, meanwhile, had gone to Wei, hoping that his military knowledge would stand him in good stead. But the Marquis of Wei said to himself -- 'Mine is a weak State hedged in by powerful ones.

'My method of preserving tranquility is to show subservience to the larger States and to conciliate the lesser ones. If I were to rely on armed force, I could only expect utter destruction. I must not allow this man to depart unscathed, or he may find his way to some other State and be a terrible thorn in my side.' So, without more ado, he cut off his feet and sent him back to Lu.
~ Lionel Giles translation via Terebess Asia Online ~

Go here to read the introductory post to the chapters of the Book of Lieh Tzu.