Now every moral virtue observes the rational mean in the matter about which it is concerned. Hence it belongs to fortitude that man should moderate his fear according to reason, namely that he should fear what he ought, and when he ought, and so forth.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic fear virtue
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

“Since then fortitude has fear opposed to it on the one side and daring on the other, it seems that fearlessness is not opposed thereto.
On the contrary, The Philosopher (Ethic. iii) reckons fearlessness to be opposed to fortitude.
I answer that, As stated above (Q. 123, A. 3) , fortitude is concerned about fear and daring. Now every moral virtue observes the rational mean in the matter about which it is concerned. Hence it belongs to fortitude that man should moderate his fear according to reason, namely that he should fear what he ought, and when he ought, and so forth. Now this mode of reason may be corrupted either by excess or by deficiency. Wherefore just as timidity is opposed to fortitude by excess of fear, in so far as a man fears what he ought not, and as he ought not, so too fearlessness is opposed thereto by deficiency of fear, in so far as a man fears not what he ought to fear.
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