For virtue is a perfect habit, by which it never happens that anything but good is done
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic virtue habit
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

“Yet, in man, that which he acquires by use, in his memory and other sensitive powers of apprehension, is not a habit properly so called, but something annexed to the habits of the intellective faculty, as we have said above (Q. 50, A. 4, ad 3) . Nevertheless even if there be habits in such powers, they cannot be virtues. For virtue is a perfect habit, by which it never happens that anything but good is done: and so virtue must needs be in that power which consummates the good act. But the knowledge of truth is not consummated in the sensitive powers of apprehension: for such powers prepare the way to the intellective knowledge.” source