Secondly, because power has relation to good and evil: whereas happiness is man's proper and perfect good. Wherefore some happiness might consist in the good use of power, which is by virtue, rather than in power itself.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic happiness evil
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

“I answer that, It is impossible for happiness to consist in power; and this for two reasons. First because power has the nature of principle, as is stated in Metaph. v, 12, whereas happiness has the nature of last end. Secondly, because power has relation to good and evil: whereas happiness is man's proper and perfect good. Wherefore some happiness might consist in the good use of power, which is by virtue, rather than in power itself. Now four general reasons may be given to prove that happiness consists in none of the foregoing external goods. First, because, since happiness is man's supreme good, it is incompatible with any evil.” source