For man needs to be perfected by virtues in all his parts, and this not only as regards the acts of reason, of which counsel is one, but also as regards the passions of the sensitive appetite, which are still more imperfect.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic passion 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

“Hence both the aforesaid processes are contrary to euboulia, as the Philosopher declares (Ethic. vi, 9) . Reply Obj. 2: Although virtue is essentially a perfection, it does not follow that whatever is the matter of a virtue implies perfection. For man needs to be perfected by virtues in all his parts, and this not only as regards the acts of reason, of which counsel is one, but also as regards the passions of the sensitive appetite, which are still more imperfect. It may also be replied that human virtue is a perfection according to the mode of man, who is unable by simple insight to comprehend with certainty the truth of things, especially in matters of action which are contingent.” source