Si hay victoria en vencer al enemigo, la hay más cuando el hombre se vence a si mismo.

[If there is victory in overcoming the enemy, there is a greater victory when a man overcomes himself.]

—José de San Martín

Quoted in the original, because the Spanish has a poetic grace and snap and style that does not come through in the translation. But then, generals and poets have more in common than the poets would care to admit.