1. By the word religion we may signify the virtue which disposes us to worship God; or we may signify a system of truths, laws, and practices by which this virtue is regulated and exercised. In this latter meaning, the Christian religion is that system of truths, laws, and practices for the worship of God which was instituted by our Lord Jesus Christ. It is taught in its fulness by the Catholic Church, and by the Catholic Church alone; that is by that conspicuous body of Christians which, while existing in all nations, and comprising as many members as all the other Christian bodies taken together, is yet perfectly united in doctrine and worship by submission to one Supreme Pontiff the Pope of Rome. For the word Catholic (kata through, holos whole) means 'universal'; and therefore this name cannot be claimed without self-contradiction by any very limited body of men. The term "Roman" is often prefixed to the name of the Catholic Church, not to distinguish, it from other Catholic churches, -- for there is evidently only one universal Church, -- but to emphasize the fact that this vast body of worshippers is united in obedience to the one Bishop of Rome.
2. The study of the Catholic religion is begun by the children of the Church from the first dawn of reason; and such is its importance, such also are its beneficial results, that it should be continued by them through life. We are now entering on a systematic study of this religion; and we shall make this study as scientific as the brevity of the present work allows. Science examines into the reasons of things; it considers, not only what an object is, but why it is such, and how it came to be such. The scientific study of the Catholic religion therefore examines, not only what this religion is, and in particular what doctrines it teaches, but also how it came to be what it is, and why it teaches every one of these doctrines. It accounts for every point, as far as this is possible, from the principles of reason and of revelation.
3. The attitude of mind on the part of Catholics toward the Church is one of deep reverence, of love, and of perfect docility, such as every dutiful child cherishes in regard to its parents. Well instructed Catholics can see no reason why they should distrust her guidance; and they would consider it as unwarrantable in them to question her authority, as it would be for sons and daughters of a respectable family to ask their parents for proofs of their right to govern the home. Catholics, therefore, do not study the claims and the doctrines of the Church in a doubting spirit, but only as scientific students, that they may understand them distinctly and know how to explain and prove them to others.
4. But non-Catholics approach the Church as inquirers, looking, in a matter which is of the highest importance, for reliable guidance, such as they have not in their sects. For the sects do not profess to be infallible; they require that every man shall judge for himself. It is therefore the duty, as well as the interest, of all non-Catholics to search most carefully for the true religion. To do so successfully, they should rid themselves of all prejudices, and examine with earnestness and perfect impartiality the claims of so remarkable an institution as the Catholic Church evidently is. They should accompany their inquiries with humble prayer, that God may enlighten their minds and strengthen their wills. For it requires grace to know and follow the guide divinely appointed to lead men to Heaven; and grace is to be obtained by prayer.
5. The systematic study of the Catholic religion is usually divided into three parts. The first examines the reasons why all men should accept the claim to infallible teaching on the part of the Catholic Church; the second considers all her doctrines in detail; the third explains the duties imposed upon her members. We shall treat these parts respectively under the titles of, 1. The teaching authority, 2. The doctrines of the Catholic Church, 3. The duties of Catholics.
The first part of our work will embrace the study: 1. of the Christian revelation, and of the credentials by which it is known to be from God; 2. Of the Catholic Church, as the Heaven-appointed teacher of the Christian revelation.
Under this head we are to consider: 1. The nature of revelation; 2. The credentials of revelation; 3. Pre-Christian revelations; 4. The Christian Revelation; 5. The records of the Christian Revelation; 6. The credentials of the Christian revelation; 7. The miraculous spread of the Christian revelation.