"As a matter of self-preservation, a man needs good friends or ardent enemies, for the former instruc..." — Diogenes

The sun too penetrates into privies, but is not polluted by them.

Wise kings generally have wise counselors; and he must be a wise man himself who is capable of distinguishing one.

It takes a wise man to discover a wise man.

Wise leaders generally have wise counselors because it takes a wise person themselves to distinguish them.