Father Thomas Pegues states that, in order to live a virtuous life by avoiding a life of sin, a person needs these exterior helps: “laws which direct him, and grace which helps him on his journey.” Here and in the following three posts, we read how Father Pegues summarizes St. Thomas Aquinas’ teaching on law, which is found in St. Thomas’ Treatise on Law (Summa Theologica I-II, 90-108). After that, we shall look at his teaching on grace in his Treatise On Grace (Summa Theologica I-II, 109-114).
First, Father Pegues gives St. Thomas’ definition of law: a law is “an order of reason, for the common good, made and promulgated by one in authority.” Notice that there are four parts to this: (1) a law is an order of reason; (2) it is made for the common good; (3) it is made by one who has authority to make such a law; and (4) it is promulgated, that is, made known to those obliged to obey it.
Father Pegues elaborates on these four parts as follows. First, “an order or a commandment contrary to reason can never be a law; it is an act of despotism or of tyranny.” Second, a law is ordained to the common good because it “provides first of all for the good of the whole community, and does not concern itself with a part thereof or of the individual, except in so far as a part or an individual concurs in the general good.” Third, “it emanates from him upon whom it is incumbent to be mindful of the common good as if it were his own private good.” Fourth, “for a law to bind it is necessary that it be promulgated in such a way that it come to the knowledge of those whom it concerns. If, through one’s own fault, one is ignorant of the law, one is not excused from obeying the law.” Therefore, “it is very important to study the laws that concern us.”
There are four kinds of law that concern us: the eternal law, the natural law, human law, and the divine law. The eternal law is “the supreme law which rules all things, and on which all other laws depend, for these latter are only derivations or particular manifestations thereof. The eternal law is in God. It is manifested by the very order of things such as is found in the world.” The natural law is “that inborn light of man’s practical reason by which he is able to direct himself and to act with knowledge consciously in such wise that his acts execute the eternal law.” Human laws are “ordinations of reason made for the common good of this or that society of human beings.” And the divine law is “the law given to men by God who manifests Himself supernaturally.”
Quotations from Thomas Pegues, Catechism of the “Summa Theologica” of Saint Thomas Aquinas, trans. Aelred Whitacre (New York: Benziger, 1922).