《礼记·玉藻》
凡吃果实，要让君子先吃，因为果实是大地所生，好坏容易分辨，用不着自己先尝；凡吃熟食，要先为君子尝食，因为熟食是人所加工，味道如何，必尝而后知，家里有了喜庆之事，但如果没有国君的赏赐，就不敢接受亲友的道贺。
君赐车马，乘以拜赐；衣服，服以拜赐；君未有命，弗敢即乘服也。
When eating fruit, let the gentleman eat first, because fruit is grown from the earth and it is easy to distinguish between good and bad, so there is no need to taste it yourself first. When eating cooked food, offer the gentleman some first, because cooked food is made by humans and you must taste it to know how it tastes. If there is a happy event in the family, but there is no reward from the emperor, do not accept congratulations from relatives and friends.