Zigong asked about friends. Confucius said: “Advise them loyally and guide them tactfully. If that fails, stop: do not expose yourself to humiliation.”
Zengzi said: “A leader attracts friends through his cultural refinement, and looks to his friends for support in nurturing his goodness.”
Book 12 of the Analects finishes with some advice on friendship from Confucius and his disciple Zengzi.
The key is to provide each other with mutual guidance and support in the pursuit of goodness without risking “humiliation” and, as Ziyou warned in Chapter XXVI of Book 4, “estrangement”, by going too far.
Both Confucius and Zengzi were, of course, talking about the “right” sort of friends who shared the same values and commitment to cultivating their virtue. Who know friendship could be so serious?