Discourses, "How We May Discover the Duties of Life from Names" (§3)

“Next to this, if you are a senator of any state, remember that you are a senator; if a youth, that you are a youth; if an old man, that you are an old man; for each of such names, if it comes to be examined, marks out the proper duties. But if you go and blame your brother, I say to you, You have forgotten who you are and what is your name.”