Hatred is increased by being reciprocated, and can on the other hand be destroyed by love.
 Baruch Spinoza, Ethics (1677). copy citation

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Author Baruch Spinoza
Source Ethics
Topic love
Date 1677
Language English
Reference
Note Translated by R. H. M. Elwes
Weblink http://www.gutenberg.org/files/3800/3800-h/3800-h.htm

Context

“hence he will endeavour, as far as he can, to conceive this cause of honour, or to regard it as actually existing. But, by the hypothesis, he conceives something else, which excludes the existence of the said cause of honour: wherefore he will thereat feel pain (III. xix.) . Q.E.D. PROP. XLIII. Hatred is increased by being reciprocated, and can on the other hand be destroyed by love. Proof.—He who conceives, that an object of his hatred hates him in return, will thereupon feel a new hatred, while the former hatred (by hypothesis) still remains (III. xl.) . But if, on the other hand, he conceives that the object of hate loves him, he will to this extent” source