But hatred is increased by being reciprocated, and can be quenched by love (III.

xliii.), so that hatred may pass into love (III.

xliv.); therefore he who lives under the guidance of reason will endeavour to repay hatred with love, that is, with kindness.
Q.E.D.
Note .-- He who chooses to avenge wrongs with hatred is assuredly wretched.

But he, who strives to conquer hatred with love, fights his battle in joy and confidence; he withstands many as easily as one, and has very little need of fortune's aid.
Those whom he vanquishes yield joyfully, not through failure, but through increase in their powers; all these consequences follow so plainly from the mere definitions of love and understanding, that I have no need to prove them in detail.
PROP.XLVII.

Emotions of hope and fear cannot be in themselves good.
Proof .-- Emotions of hope and fear cannot exist without pain.
For fear is pain (Def.