Cette citation est attribuée à François de La Rochefoucauld, extraite de ses 'Réflexions ou sentences et maximes morales' (1665), une œuvre majeure de la littérature morale française du XVIIe siècle.
"One should value virtues more by their principles than by their effects. Services should be judged less by the advantage gained by the obliged person than by the sacrifice made by the obliging one."