Letters 74.21

Love reason! The love of reason will arm you against the greatest hardships. Wild beasts dash against the hunter’s spear through love of their young, and it is their wildness and their unpremeditated onrush that keep them from being tamed; often a desire for glory has stirred the mind of youth to despise both sword and stake; the mere vision and semblance of virtue impel certain men to a self-imposed death. In proportion as reason is stouter and steadier than any of these emotions, so much the more forcefully will she make her way through the midst of utter terrors and dangers.

Seneca, Letters to Lucilius 74.21, translated by Richard Mott Gummere