《后汉书·列传·张曹郑列传》
既是这样，那么所谓 公 就是具有仁德之人的正当名号。不必做太尉、司徒、司空的大夫才称为 公 。
然则公者仁德之正号，不必三事大夫也。
If that is the case, then the so-called "gong" is the proper title for a person of benevolent virtue. It is not necessary to be a high officer like grand minister, minister of works, or minister of justice in order to be called a "gong".