I answer that, The nature of human virtue consists in making a man's deed good. Consequently whenever we find a special aspect of goodness in human acts, it is necessary that man be disposed thereto by a special virtue.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic goodness 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

“But simplicity is not a special virtue, since it rectifies the intention, and that is required in every virtue. Therefore neither is truth a special virtue.
On the contrary, It is numbered together with other virtues (Ethic. ii, 7) .
I answer that, The nature of human virtue consists in making a man's deed good. Consequently whenever we find a special aspect of goodness in human acts, it is necessary that man be disposed thereto by a special virtue. And since according to Augustine (De Nat. Boni iii) good consists in order, it follows that a special aspect of good will be found where there is a special order. Now there is a special order whereby our externals, whether words or deeds, are duly ordered in relation to some thing, as sign to thing signified: and thereto man is perfected by the virtue of truth.” source