Natural love is said to be of the end, not as of that end to which good is willed, but rather as of that good which one wills for oneself, and in consequence for another, as united to oneself.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic love consequences
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17611/pg17611-images.html

Context

“Consequently he loves more what is numerically one with himself, than what is one only generically or specifically. But it is natural for him to have a like love for another as for himself, in this respect, that as he loves self in wishing well to self, so he loves another in wishing well to him. Reply Obj. 3: Natural love is said to be of the end, not as of that end to which good is willed, but rather as of that good which one wills for oneself, and in consequence for another, as united to oneself. Nor can such natural love be stripped from the wicked angels, without their still retaining a natural affection towards the good angels, in so far as they share the same nature with them. But they hate them, in so far as they are unlike them according to righteousness and unrighteousness.” source