Is keeping the Ten Commandments all that is required of us by God? No.
Avoiding sin is a good thing and necessary for happiness in this life and in the next; however, it is only one half of the equation.
If you go to the doctor and are told the good news that you have no disease, does that mean you are completely healthy? Being free of disease or injury is very important, but any good physician will also tell you to cultivate healthy behavior. Lacking the negative must be accompanied by adding the positive. Exercise, rest, and eating properly will promote and sustain good health and will help fight disease.
Both doing good and avoiding evil make up the entire formula. One side is not enough. We must do both, just as we must avoid what is unhealthy and do what is healthy to keep our bodies in optimum shape. Look at sin as a disease of the soul. Mortal sin is a deadly sin as it kills the life of grace.
Grace is to the soul what blood is to the heart or oxygen is to the lungs. Mortal sin removes life support from the soul by killing the grace that was there. It is like a malignant tumor on the soul. Venial sin is less lethal and is like a benign tumor. Even though benign, no one wants a non-lethal growth on their face. Similarly, the Christian needs to be equally concerned about his venial sins and not just the mortal ones.
The Ten Commandments help us avoid sin, but what helps us do good? This is where the moral virtues come to our rescue. Even the pagan Greeks and Romans realized the value of living a virtuous life. For example, the Roman philosophy of Stoicism endorsed living the private and public virtues to promote harmony within the person, the family, and the state (or empire).
The ancient philosophers and early Christian theologians distilled four cardinal virtues which were invaluable to a morally good life. They are called “cardinal” from the Latin root of the word, cardo, meaning “hinge.” The virtuous life hinges on these four moral virtues.
They are prudence (prudentia in Latin; phronésis in Greek), justice (iustitia in Latin; dikaiosyné in Greek), fortitude or courage (fortitude in Latin; andreia in Greek), and temperance or moderation (temperantia in Latin; sóphrosyné in Greek).