Which sentence best explains why the two parallel instances in these lines form an analogy?

"as the sandwich islander believes that the strength and valor of the enemy he kills
passes into himself, so we gain the strength of the temptation we resist."
(from essays by ralph waldo emerson)

both entail endangering oneself for personal gain.
both balance a loss to one side with a gain to the other.
both require the subjects to make spontaneous choices.
both involve gain by overcoming opposition.