In preparing and instructing men in the teachings of Christ the Lord, the Fathers began by explaining the meaning of faith. Following their example, we have thought it well to treat first what pertains to that virtue.
Though the word faith has a variety of meanings in the Sacred Scriptures, we here speak only of that faith by which we yield our entire assent to whatever has been divinely revealed.
That faith thus understood is necessary to salvation no man can reasonably doubt, particularly since it is written: Without faith it is impossible to please God. For as the end proposed to man as his ultimate happiness is far above the reach of human understanding, it was therefore necessary that it should be made known to him by God. This knowledge, however, is nothing else than faith, by which we yield our unhesitating assent to whatever the authority of our Holy Mother the Church teaches us to have been revealed by God; for the faithful cannot doubt those things of which God, who is truth itself, is the author. Hence we see the great difference that exists between this faith which we give to God and that which we yield to the writers of human history.
Faith differs in degree; for we read in Scripture these words: O thou of little faith, why didst thou doubt; and Great is thy faith; and Increase our faith. It also differs in dignity, for we read: Faith without works is dead; and, Faith that worketh by charity. But although faith is so comprehensive, it is yet the same in kind, and the full force of its definition applies equally to all its varieties. How fruitful it is and how great are the advantages we may derive from it we shall point out when explaining the Articles of the Creed.
Now the chief truths which Christians ought to hold are those which the holy Apostles, the leaders and teachers of the faith, inspired by the Holy Ghost' have divided into the twelve Articles of the Creed. For having received a command from the Lord to go forth into the whole world, as His ambassadors, and preach the Gospel to every creature, they thought it advisable to draw up a formula of Christian faith, that all might think and speak the same thing, and that among those whom they should have called to the unity of the faith no schisms would exist, but that they should be perfect in the same mind, and in the same judgment.
This profession of Christian faith and hope, drawn up by themselves, the Apostles called a symbol; either because it was made up of various parts, each of which was contributed by an Apostle, or because by it, as by a common sign and watchword, they might easily distinguish deserters from the faith and false brethren unawares brought in, adulterating the word of God, from those who had truly bound themselves by oath to serve under the banner of Christ.
Christianity proposes to the faithful many truths which, either separately or in general, must be held with an assured and firm faith. Among these what must first and necessarily be believed by all is that which God Himself has taught us as the foundation and summary of truth concerning the unity of the Divine Essence, the distinction of Three Persons, and the actions which are peculiarly attributed to each. The pastor should teach that the Apostles, Creed briefly comprehends the doctrine of this mystery.
For, as has been observed by our predecessors in the faith, who have treated this subject with great piety and accuracy, the Creed seems to be divided into three principal parts: one describing the First Person of the Divine Nature, and the stupendous work of the creation; another, the Second Person, and the mystery of man's redemption; a third, the Third Person, the head and source of our sanctification; the whole being expressed in various and most appropriate propositions. These propositions are called Articles, from a comparison frequently used by the Fathers; for as the members of the body are divided by joints (articuli), so in this profession of faith, whatever is to be believed distinctly and separately from anything else is rightly and suitably called an Article.