Father Pegues continues his discussion of the virtue of faith by defining the means by which are interpreted the truths of faith revealed by the Word of God.
He states: “The Sovereign Pontiff, and through him the Catholic Church in its universal teaching . . . unerringly interprets the right sense of the word of God whether contained in the Scriptures or elsewhere.” These cannot err, because “God Himself has wished that they should be infallible. . . . Otherwise, men would not have the necessary means of reaching, without fail, the supernatural end to which He has called them.” When one says that “the Pope and the Church are infallible in matters of faith and morals,” one means that “the Pope and the Church can never be deceived, nor can they deceive us, when they give or interpret the word of God in matters that treat of the essential truths which regard faith or conduct.” The Apostles’ Creed is “a resume of these essential truths which treat of faith and conduct.”
What does Father Pegues mean by “the Church”? We might note that the Second Vatican Council’s Dogmatic Constitution on the Church, Lumen gentium (No. 25), teaches that the infallibility which Christ promised to the Church is present, not only in the pope in virtue of his office as supreme pastor and teacher, but also in the body of bishops when they and the pope together exercise their teaching authority (Magisterium in Latin) in proposing a particular doctrine to the faithful concerning a matter of faith or morals.
Father Pegues notes that heretics (those who deny some, but not all, truths of the faith) cannot make an act of faith, because “even though in their minds they assent to such and such a point of revealed doctrine, they do not give this assent on the word of God, but on their own private judgment.” Apostates (those who repudiate the faith entirely) cannot make an act of faith, because “their mind rejects entirely what formerly they believed on the word of God.” But sinners can make an act of faith if their sin is not a sin against faith. “A sin against faith consists in not wishing to submit one’s mind to the word of God through homage or through love for God’s word.” Blasphemy, for example, is a sin against faith, for it consists in “the uttering of some word that dishonours God or His saints.”
One is always at fault for not submitting his mind to the word of God, for “he resists the actual grace God offers inviting him to make this act of submission.” God offers this actual grace to every human person, “although in different degrees and as it pleases God to distribute it according to the designs of His Providence.”
Quotations from Thomas Pegues, Catechism of the “Summa Theologica” of Saint Thomas Aquinas, trans. Aelred Whitacre (New York: Benziger, 1922).