Why are prudence, justice, fortitude, and temperance called Cardinal Virtues?
Prudence, justice, temperance, and fortitude are called Cardinal Virtues because they are the key virtues upon which all the other virtues hinge or depend. In Latin, “cardo” means “hinge.” The other virtues of human morality, such as obedience, patience, humility, truthfulness, and patriotism, are related to the Cardinal Virtues.
A virtue begins as the capacity to make particular virtuous acts. Repeated acts become habits or permanent dispositions inclining us to do a particular good and to avoid a particular evil.
A virtue acquired by our own efforts—that is, through our conscious development of a particular good habit—is called a natural virtue. Supernatural virtues, on the other hand, are capacities or habits which God directly infuses into our souls, with no effort on our part. We need to ask Jesus for the fullness of grace of these virtues. Even when God gives us the grace of supernatural virtues, we must work to strengthen our virtues, bringing them to maturity and perfection.