When we take a very great interest in a thing, we look upon it as our own good
 Thomas Aquinas, Summa Theologica (1274). copy citation

add
Author Thomas Aquinas
Source Summa Theologica
Topic interest good
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17897/pg17897-images.html

Context

“If we are angry with those who harm others, and seek to be avenged on them, it is because those who are injured belong in some way to us: either by some kinship or friendship, or at least because of the nature we have in common. Reply Obj. 3: When we take a very great interest in a thing, we look upon it as our own good; so that if anyone despise it, it seems as though we ourselves were despised and injured. Reply Obj. 4: Silence provokes the insulter to anger when he thinks it is due to contempt, as though his anger were slighted:” source