St. Thomas, in Question 94 (I-II) explains, quoting St. Augustine, that the natural law cannot be blotted out or effaced, written as it is on our hearts. What’s then, is the importance, in light of the permanence of natural law, of our intentional growth in virtue?
“Virtue is that powers utmost extent. The utmost extent is that to which a power reaches in order to perform a perfect operation, and that in turn is the operation’s being good. Clearly then each things virtue is that through which it produces a good operation. (Disputed Questions on Virtue, Aquinas).”
To be good is simply to mean that which we are meant to be. A good clock keeps time because that is what a clock is meant to do. A good man, likewise, is meant by nature to do certain things. But unlike artifacts, man has free will and with that, habits.
But since man is endowed with intelligence and determines his own ends, it is up to him to put himself in tune with the ends necessarily demanded by his nature. This means that there is, by the very virtue of human nature, an order or a disposition which human reason can discover and according to which the human will must act in order to attune itself to the essential and necessary ends of the human being. (Man and the State, J. Maritain)
Of course, for Thomas Aquinas, habits are more than they are to us today. Nevertheless, as creatures who, to some extent, determine their own end through free will, but are also made for a purpose by their Creator, we must develop habits that lead us to act in conformity with that end, or rather, the development of virtue helps us to attain the one end that is both determined for us and that we determine ourselves towards.
Servias Pinckaers uses the wonderful example of a piano player as a means to show what virtue can do for someone who seeks true freedom towards a specific end:
In the beginning the child, despite the desire to learn will often feel that the lessons and exercises as a constraint imposed on freedom and the attractions of the moment. There are times when practice has to be insisted upon…Of course, anyone is free to bang out notes haphazardly on the piano, as the fancy strikes him. But this is a rudimentary, savage sort of freedom… On the other hand, the person who really possesses the art of playing the piano has acquired a new freedom. (The Sources of Christian Ethics, p.355)
We see, then, that to truly be free to attain the very ends we were both made for and should aspire to attain to, that our freedom involves both a responsibility and a joy in becoming what we are meant to be. It should come as no surprise that, at the same time a new teaching on freedom overtook society (a freedom which emphasizes indifference rather than excellence) the virtues fell out of common knowledge and pursuit.
If we are to once again become a culture that seeks excellence, we must be a culture that strives after virtue. We are meant to be something, and we are meant to have a part becoming that something. We are truly both what we are (as created) and what we make of ourselves: a sort of theistic existentialism. Made in the image of God, we are meant to be free, but free to be what He made us to be.