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Moral Law

Updated: Jan 11, 2023

St. Thomas Aquinas described a law as a rule that induced or restrained an action (ST I-II, Q. 90, Art. 1, s. c.). It is easy to see how Christian morality can be reduced to a series of commands that dictate what actions an agent is obliged to undertake under a given circumstance. In fact, there is a certain sense to this approach for the novice, by which they can easily digest the wisdom of those who came before them. However, “the moral law is a work of divine Wisdom” that leads toward happiness and the ultimate end of man (CCC 1950). Law in moral theology is not reducible to externally opposed obligations, but a participation in divine Wisdom.

There is an eternal law that emanates from God, and this law governs the universe. All things partake of this divine law, but most especially, rational creatures such as ourselves. This share of eternal reason endows us with the “natural inclination to [our] proper act and end” (ST I-II, Q. 91, Art. 2, co.). This participation which directs our reason toward the good that we should do is known as natural law. The practical application of human reason is the source of human laws. According to Aquinas, there is also the Divine law which directs us toward our ends that would not be knowable by our natural faculties alone (ST I-II, Q. 91, Art. 4, co.). This Divine law also provides justice in ways that human law simply is not able due to limitations of human knowledge.

Natural law is at odds with many notions of morality which are understood as precepts that are externally imposed by a society. Rather, the natural law is an interior law that points each person toward their ultimate good and happiness. Yet, this law is not at odds with our freedom, but our natural inclinations enable our freedom for excellence. True human freedom is not a freedom from without, but from within. We are free to move toward that good that will fulfill us and are attracted to that goodness.

The natural law inclines us to yearn for goodness and everything that is good attracts us, even if we are not always capable of recognizing the greatest goods. From this we find the inclination to preserve our own existence and to transmit life through the gift of our sexuality. We have a natural love of self and desire our own thriving. We want to share ourselves with others through the formation of the family which is the first model we see for love. Similar to the search for goodness, we also drawn toward the truth which allows us communion with other rational beings. Finally, our drive from communion inclines us toward social life. Our natural inclination is to be in relationship. We are attracted to the good, to love others and to be loved.

The role of natural law guides us throughout the stages of human development. At first, it is useful to contain our sinful inclinations with external obligation, yet, our development should not stop here. We must make that law interiorized so that we do not follow it out of fear of punishment, but by attraction to goodness. Finally, “the law becomes... the instrument of the Spirit who infuses into our acts their full moral and spiritual excellence” (Pinckaers 110).


Works Cited

Aquinas, Thomas. SUMMA THEOLOGIAE, Kevin Knight, 2017,

Catholic Church. Catechism of the Catholic Church. 2nd ed. Vatican: Libreria Editrice Vaticana, 2012.

Pinckaers, Servais Théodore. Morality: the Catholic View. St. Augustine's Press, 2001.


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