When sending his greetings to someone in another state, he would bow twice before sending the messenger on his way.
When Ji Kangzi sent him some medicine, Confucius bowed as he accepted the gift but said: “Since I don’t know what this substance is, I dare not taste it.”
Some versions of the Analects put these two passages together into a single chapter. I am not sure I agree, but I can see the justification because both of them cover ritual behavior when sending and receiving messages and gifts.
Bowing even once before sending out a message doesn’t make any sense in our world of ubiquitous connectivity, but at a time when long-distance missives were relatively rare, it is easy to understand why a formal ritual would be developed to mark such an event. The two bows were to show respect to the intended recipient – perhaps injected with a dash of hope that the messenger would survive the long and potentially dangerous journey ahead of him.
When receiving a gift of medicine from Ji Kangzi, a member of one of the three most powerful clans in his home state of Lu, Confucius was put in a highly delicate situation. On the one hand, the rites dictated that there was no way he could decline a (no doubt valuable) gift from a man he did not respect, but on the other hand he had to find a skillful way of making it known that he didn’t truly accept it either so that he wouldn’t be under any (unspoken) obligation to return the favor at some later date.
Confucius’s response that he dare not taste the medicine because he doesn’t know what it is achieves this goal while also making his suspicions of Ji Kangzi’s motives in sending it very clear. I would love to have been a fly on the wall when the poor messenger reported his comments to his lord.