Book of Rites, Liyun Ninth: "The trip to the Avenue is also for the public. Choose talents and abilities, make friends and mend fences, so an old friend is not only close to his relatives, but also an only son and son, so that the old will have an end, the young will be strong and useful, and those who are widowed, lonely and sick will be supported. Men have points, women have returns. If the goods are abandoned to the ground, there is no need to hide them in yourself; You don't have to do it for yourself. Therefore, it is called "Datong" to seek closure without prosperity, to steal thieves without doing anything, and therefore to go outside without closing.