765. The points about which explicit faith is required can be reduced to four heads (see Catechism of the Council of Trent). These heads are:
(a) The things to be believed: “Preach the Gospel to every creature. He that believeth shall be saved” (Mark, xvi. 15). The Gospel doctrine is summarized in the Apostles’ Creed;
(b) The things to be done: “Teach them to observe all things whatsoever I have commanded you” (Matt., xxviii. 20). The Ten Commandments (see Vol. II) are called the epitome of the whole law;
(c) The ordinances to be observed; “Baptize them in the name of the Father, and of the Son, and of the Holy Ghost” (Matt, xxviii. 19). The Seven Sacraments are the sacred instruments through which the merits of the Passion of Christ are applied to the soul;
(d) The petitions to be made to God: “Thus shall you pray: Our Father, etc.” (Matt., vi. 9). The prayer (see Vol. II) given us by Christ teaches us both the manner of prayer and the requests that should be offered.
766. Faith in the revelation given by God is necessary for salvation (Heb., xi. 6), but in the usual providence of God faith cannot be had or safeguarded without short formulas of its principal doctrines.
(a) Faith cannot be received without such formulas, because, its doctrines being many and frequently difficult and the study of all scripture and Tradition being impossible for most persons, a list of short and clear propositions of revealed truths (Creed) is needed that the faith may be proposed and accepted.
(b) Faith cannot be retained without such formulas, because, being unchanging in itself and yet for all times and places, its doctrines would be easily corrupted if there were not an official standard (Symbol) by which both truth and error could be at once recognized (I Cor., i. 10; II Tim., i. 13).
767. The formulas of Christian teaching as summarized in the Creeds, since they must be brief and orderly, are divided into short and connected propositions, which are therefore known as articles. Brevity being the character of Creeds, not all revealed truths are expressed in them as articles, but only those that have the following characteristics:
(a) An article of the Creed deals with one of the two main objects of belief, namely, the end of man, which is eternal life (Heb., xi. 1), and the means thereto, which is Jesus Christ (John, xvii. 3). Other things, which are proposed for faith, not for their own sake, but only on account of their relation to these two main objects (e.g., the wandering of the Israelites in the desert, the details of the journeys of St. Paul, etc.), are not mentioned in the Creeds.