Virtue which is referred to being is not proper to man; but only that virtue which is referred to works of reason, which are proper to man.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic virtue reason
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

“Hence virtue, inasmuch as it is a suitable disposition of the soul, is like health and beauty, which are suitable dispositions of the body. But this does not hinder virtue from being a principle of operation. Reply Obj. 2: Virtue which is referred to being is not proper to man; but only that virtue which is referred to works of reason, which are proper to man. Reply Obj. 3: As God's substance is His act, the highest likeness of man to God is in respect of some operation. Wherefore, as we have said above (Q. 3, A. 2) , happiness or bliss by which man is made most perfectly conformed to God, and which is the end of human life, consists in an operation.” source