But the supreme good is in nature, and is the cause of every good, as was shown above (Q. 2, A. 3; Q. 6, AA. 2, 4). Therefore, also, there is a supreme evil opposed to it as the cause of every evil.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic evil good
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

“33:15: "Good is set against evil, and life against death; so also is the sinner against a just man." Therefore there are many contrary principles, one of good, the other of evil.
Obj. 2: Further, if one contrary is in nature, so is the other. But the supreme good is in nature, and is the cause of every good, as was shown above (Q. 2, A. 3; Q. 6, AA. 2, 4). Therefore, also, there is a supreme evil opposed to it as the cause of every evil. Obj. 3: Further, as we find good and better things, so we find evil and worse. But good and better are so considered in relation to what is best. Therefore evil and worse are so considered in relation to some supreme evil.
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