The wit here cuts deeper than a mere reversal of the friendship maxim—Wilde suggests that enemies, like allies, reveal who we are. When you clash with someone, you're not simply encountering opposition; you're choosing what values you'll defend, what hills you'll die on, what compromises you'll reject. A person who argues with everyone holds up a mirror to their own rigidity, while someone who draws enemies only from those who genuinely threaten what matters most has performed an act of self-knowledge. Think of the professional who quits over a principle: their chosen enemies—the boss willing to cut corners, the client demanding dishonesty—become the clearest statement of their character.