Theological Virtues

Etymologically, Aquinas derived "virtue" from the same root as the
Latin vir [man] and vis [power], suggesting that in its primitive
sense virtue implied the possession of such masculine qualities as
strength and courage and, in the moral order, of goodness and human
perfection.

In the patristic period, theological virtues were the subject of
frequent writing and, in Pelagian times, of controversy. The
commentaries of the Fathers on St. Paul offer a complete treatise on
every phase of faith, hope and charity; and St. Augustine's
Enchiridion or Manual of the Christian Religion was always
referred to by him as "a book on Faith, Hope, and Charity." For
Augustine, therefore, a summary of these virtues was an epitome of
the essentials of Christianity.

However a scientific study was not made until the Middle Ages, in the
great Summa of Peter Lombard, Peter of Poitiers, William of Auxerre
and Alexander of Hales, terminating in the definitive work of St.
Thomas. His analysis of theological virtue remains standard, and
figures extensively in all his major writings, especially the Summa
Theologica.

St. Thomas defines virtue as "a good habit bearing on activity," or a
good faculty-habit [habitus operativus bonus]. Generic to the
concept of virtue, then, is the element of habit, which stands in a
special relation to the soul, whether in the natural order or
elevated to the divine life by grace.

The soul is the remote principle or source of all our activities;
faculties are the proximate sources built into the soul by nature;
habits are still more immediate principles added to the faculties
either by personal endeavor or by supernatural infusion from God.
Consequently the soul helps the man, faculties help the soul, and
habits help the faculties.