This essay argues that the truly wise person cannot be injured or insulted. Addressed to Serenus, it develops the Stoic paradox that external events — including insults, losses, and physical harm — cannot touch the inner citadel of a well-ordered mind.
Seneca uses vivid examples and analogies to distinguish between real injury and mere inconvenience, building a case for a kind of invulnerability grounded in virtue rather than indifference.
"All this the wise man escapes, for he knows nothing of directing his life either toward hope or toward fear."
— On the Firmness of a Wise Man, 9