Gongshan Furao, using the town of Bi as a stronghold, launched a revolt. He summoned Confucius to join him and Confucius was tempted to go. Zilu was unhappy about this and said: “We may have nowhere to go, but why must we go to join Gongshan?” Confucius said: “Since he has summoned me, it must be for some purpose. If his purpose is to employ me, perhaps I could establish a new Zhou Dynasty in the East.”
Like Yang Huo in Chapter I of Book 17, Gongshan Furao was another disaffected retainer of the Ji family who rose up against them and asked Confucius to join him in a revolt. The major difference between the two men, allegedly at least, is that Gongshan planned to restore the rightful authority of the hereditary ducal family over the state of Lu whereas Yang was only interested in boosting his own power and prestige.
I say “allegedly” because most likely later followers of Confucius ascribed to Gongshan this purer motive in order to sugarcoat this astounding moral lapse of their sage. Zilu certainly has no truck with it, and is appalled that Confucius should even consider going to visit a rebel like Gongshan. Confucius, however, allows himself to believe that he can finally achieve his dream of setting up a “new Zhou Dynasty in the East.” (The original Zhou Dynasty was located in the western part of China whereas Lu was in the east.)
It is not clear whether Confucius did go to meet Gongshan, but even if he did nothing ever came out of it. A good thing too given that any form of association with a rebel like him would have destroyed Confucius’s reputation and tarnished his legacy forever.