Speaking in a general way, every passion can be called a weakness, in so far as it weakens the soul's strength and clogs the reason.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic weakness strength
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

“As stated above (Q. 82, A. 3, ad 1) , concupiscence is natural to man, in so far as it is subject to reason: whereas, in so far as it is goes beyond the bounds of reason, it is unnatural to man. Reply Obj. 4: Speaking in a general way, every passion can be called a weakness, in so far as it weakens the soul's strength and clogs the reason. Bede, however, took weakness in the strict sense, as contrary to fortitude which pertains to the irascible. Reply Obj. 5: The "difficulty" which is mentioned in this book of Augustine, includes the three wounds affecting the appetitive powers, viz.” source