There can be no true peace except where the appetite is directed to what is truly good, since every evil, though it may appear good in a way, so as to calm the appetite in some respect, has, nevertheless many defects, which cause the appetite to remain restless and disturbed. Hence true peace is only in good men and about good things.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic calm evil
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/18755/pg18755-images.html

Context

“Hence all wars are waged that men may find a more perfect peace than that which they had heretofore. Reply Obj. 3: Peace gives calm and unity to the appetite. Now just as the appetite may tend to what is good simply, or to what is good apparently, so too, peace may be either true or apparent. There can be no true peace except where the appetite is directed to what is truly good, since every evil, though it may appear good in a way, so as to calm the appetite in some respect, has, nevertheless many defects, which cause the appetite to remain restless and disturbed. Hence true peace is only in good men and about good things. The peace of the wicked is not a true peace but a semblance thereof, wherefore it is written (Wis. 14:22) : "Whereas they lived in a great war of ignorance, they call so many and so great evils peace."” source