No man wills and works evil to himself, except he apprehend it under the aspect of good.
 Thomas Aquinas, Summa Theologica (1274). copy citation

add
Author Thomas Aquinas
Source Summa Theologica
Topic evil work
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

“Wherefore they love themselves according to what they take themselves to be, while they hate that which they really are, by desiring what is contrary to reason. And in both these ways, "he that loveth iniquity hateth" not only "his own soul," but also himself. Wherefore the reply to the First Objection is evident. Reply Obj. 2: No man wills and works evil to himself, except he apprehend it under the aspect of good. For even they who kill themselves, apprehend death itself as a good, considered as putting an end to some unhappiness or pain. Reply Obj. 3: The miser hates something accidental to himself, but not for that reason does he hate himself:” source