The knowledge of God consists in the knowledge of His perfections, His works, His will, and the means of grace instituted by Him. St. Paul bids us “increase in the knowledge of God” (Col. i. 10). Now we only know God through a glass in a dark manner; only in heaven shall we see Him face to face, and have a clear knowledge of His perfections (1 Cor. xiii. 12).

1. The happiness of the angels and the saints consists in the knowledge of God.

Our Lord tells us that “this is eternal life, that they may know Thee, the only true God, and Jesus Christ Whom Thou hast sent” (John xvii. 3). This is the food of which the archangel Raphael spoke, when he said to Tobias: “I use an invisible meat and drink, which cannot be seen by men” (Tob. xii. 19). In heaven the saints and angels have an immediate knowledge of God in the beatific vision. We on earth only know God through the medium of His works and of what He has revealed to us. Our knowledge, compared with that of the saints and angels, is like the knowledge of a country that one gets from maps and pictures as compared with the knowledge of one who has himself visited it.

2. The knowledge of God is all-important, for without it there cannot be any happiness on earth, or a well-ordered life.

The knowledge of God is the food of our soul. Without it the soul feels hungry; we become discontented. He who does not possess interior peace, cannot enjoy riches, health, or any of the goods of this life; they all become distasteful to him. Yet few think about this food of the soul; they busy themselves, as Our Lord says, with the “meat that perishes” (John vi. 27). Without the knowledge of God a man is like one who walks in the dark, and stumbles at every step; he has no end or aim in life, no consolation in misfortune, and no hope in death. He cannot have any solid or lasting happiness, or any true contentment. Without a knowledge of God a well-ordered life is impossible. Just as an untilled field produces no good fruit, so a man who has not the knowledge of God can produce no good works. Ignorance and forgetfulness of God are the causes of most of the sins that men commit. Rash and false oaths, neglect of the service of God and of the sacraments, the love of gold, the sinful indulgence of the passions, are all due to willful ignorance and forgetfulness of God. Thus the prophet Osee exclaims “There is no knowledge of God in the land. Cursing and lying and killing and theft and adultery have overflowed” (Osee iv. 2, 3). And St. Ignatius of Loyola cries out, “O God, Thou joy of my soul, if only men knew Thee, they never would offend Thee,” and experience shows that in the jails the greater part of the prisoners are those who knew nothing of God. When Frederick of Prussia at length recognized that the want of the knowledge of God was the cause of the increase in crime, he exclaimed, “Then I will have religion introduced into the country.” This is why the learning and the understanding of the Catechism, which is nothing else than an abridgment of the Christian religion, is all-important. But a mere knowledge of the truths of religion is not sufficient; they must also be practiced.

3. We arrive at a right knowledge of God through faith in the truths which God has revealed.

It is true that by means of reason and from the contemplation of the creatures that God has made man can arrive at a knowledge of God (Rom. i. 20). “The heavens show forth the glory of God” (Ps. xviii. 2). But our reason is so weak and prone to err, that without revelation it is very difficult for man to attain to a clear and correct knowledge of God. What strange and perverted views of the Deity we find among heathen nations (cf. Wisd. ix. 16, 17). God therefore in His mercy comes to our aid with revelation. Through believing the truths that God has revealed, man attains to a clear and correct knowledge of God. Hence St. Anselm says, “The more I am nourished with the food of faith, the more my understanding is satisfied.” Faith is a divine light that shines in our souls (2 Cor. iv. 6). It is like a watch tower, from which we can see that which cannot be seen from the plain below; we learn respecting God that which cannot be learned by mere reason from the world around. It is a glass through which we perceive all the divine perfections. It is a staff which supports our feeble reason, and enables it to know God better. There are two books from which we gain a knowledge of God; the book of Nature, and Holy Scripture, which is the book of revelation.


If any one stands in a room behind a gauze curtain he perceives all those who are passing in the street, and they see him not. But if he makes himself known by speaking, the passers-by are able to recognize him. Such is our relation to God; He sees us, but conceals Himself from our eyes. Yet He has in many ways made Himself known to men; to Abraham, to Moses in the burning bush, to the Israelites on Mount Sinai, etc.

1. God has in His mercy in the course of ages often revealed Himself to men (Heb. i. 1-2).

God has often communicated to men a knowledge of His perfections, His decrees, and His holy will. Such revelation is called supernatural, as opposed to the natural revelation of Himself that He makes through the external world.

2. God’s revelation to man is generally made in the following way: He speaks to individuals and orders them to communicate to their fellow-men the revelation made to them.

Thus God spoke to Abraham, Noe, and Moses. He sent Noe to preach to sinful men before the Flood, He sent Moses to the Israelites when they were oppressed by Pharao. Sometimes God spoke to a number of men who were assembled together, as when He gave the law to the people on Mount Sinai, or when Our Lord was baptized by St. John and the Holy Spirit descended like a dove, a voice being heard from heaven: “This is My beloved Son, in Whom I am well pleased.” Sometimes God revealed Himself through angels, as for in stance to Tobias through the archangel Raphael. When God spoke to men, He took the visible form of a man or of an angel, or He spoke from a cloud (as on Sinai), or from a burning bush, as He did to Moses, or amid a bright light from heaven, as to St. Paul, or in the whispering of the wind, as He did to Elias, or by some interior illumination (Deut. ii. 6-8). Those to whom God revealed Himself, and who had to bear witness before others to the divine message, were called messengers from God, and often received from Him the power of working miracles and of prophecy, in proof of their divine mission. (Cf. the miracles of Moses before Pharao, of Elias, the apostles, etc.)

3. Those who were specially entrusted with the communication to men of the divine revelation were the following: the patriarchs, the prophets, Jesus Christ the Son of God (Heb. i. 1), and His apostles.

Revelation is to mankind in general what education is to individual men. Revelation corresponds to the needs of the successive stages of human development, to the infancy, childhood, and youth of mankind. The patriarchs, who had more of the nature of children, needed less in the way of precepts, and God dealt with them in more familiar fashion; the people of Israel, in whom, as in the season of youth, self-will and sensuality were strong, had to be trained by strict laws and constant correction; but when mankind had arrived at the period of manhood, then God sent His Son and introduced the law of love (1 Cor. xiii. 11; Gal. iii. 24). Of all those who declared to men the divine revelation, the Son of God was pre-eminently the true witness. He says of Himself, “For this I was born, and for this I came into the world, that I should bear testimony to the truth” (John xviii. 37). He was of all witnesses the best, because He alone had seen God (John i. 18). The apostles also had to declare to men the divine revelation. They had to bear witness of what they had seen, and above all of the resurrection of Jesus Christ (Acts x. 39). With the revelation given through Christ and His apostles, the revelation that was given for the instruction of all mankind was concluded.

4. Even since the death of Our Lord and His apostles God has often revealed Himself to men; yet these subsequent revelations are no continuation of the earlier revelation on which our faith rests.

Instances of these subsequent revelations are the appearances of Our Lord to Blessed Margaret Mary, and of Our Lady at Lourdes. Such revelations must not be too lightly credited, as men are liable to be deceived; yet they must not be rejected without examination. Many of the saints have had such revelations, i.e., St. Francis of Assisi, to whom Our Lord appeared upon the cross, and St. Anthony of Padua, in whose arms the Child Jesus deigned to rest. These private revelations were more especially given to those who were striving after perfection, in order to encourage them to greater perfection still. Yet God sometimes revealed Himself to wicked men, i.e., to Baltassar in the handwriting on the wall (Dan. v. 5, seq.). Hence a private revelation given to any one is not necessarily a mark of holiness. These revelations, moreover, were no further continuation of the revelation intended for the instruction of the whole of mankind, which ended with the death of the last of the apostles; they are rather a confirmation of truths already revealed. Thus Our Lady, when she appeared at Lourdes, proclaimed herself the “Immaculate Conception,” so confirming the dogma which Pius IX had defined four years previously, and the countless miracles and cures that have taken place there have established the truth of the apparition. Yet it is always possible that the malice of the devil may introduce deceptions into private revelations. No one is therefore bound to give to them a firmer belief (even though they have in general been approved by the Church), than he would give to the assertions of an honest and trustworthy man.

5. Revelation was necessary because, in consequence of original sin, man without revelation has never had a correct knowledge of God and of His will; and also because it was necessary that man should be prepared for the coming of the Redeemer.

The three Wise Men would never have found Christ if He had not revealed Himself to them by means of a star; so mankind would have lived far off from God, and would never have attained to a true knowledge of Him, if He had not revealed Himself to them. As the eye needs light to see things of sense, so human reason, which is the eye of the soul, needs revelation to perceive things divine (St. Augustine). Original sin and the indulgence of the senses had so dimmed human reason that it could no longer recognize God in His works (Wisd. ix. 16). This is proved by the history of paganism. The heathen worshipped countless deities, idols, beasts, and wicked men, and his worship was often immoral and horrible, as in the human sacrifices offered by him. The gods were often the patrons of vice. The greatest men among the heathens approved practices forbidden by the natural law. Thus Cicero approved of suicide, Plato of the exposing to death those children who were weak or deformed. Their theories when good were at variance with their practice. Socrates denounced polytheism, but before his death told his disciples to sacrifice a cock to Esculapius. Many of the best of the heathens recognized and lamented their ignorance of God. Besides, without a previous revelation the Saviour would have been neither known nor honored as He ought to have been known and honored; it was fitting that He should be announced beforehand, like a king coming to take possession of his kingdom. We ought indeed to be grateful to God that He has given us the light of revelation, just as a blind man is grateful to the physician who has restored his sight. Yet how many there are who willfully shut their eyes to the light of revelation even now!


1. The truths revealed by God to men were, by God’s command, proclaimed to all nations of the earth by the Catholic Church, and especially by means of the living word, that is, by preaching.
The command to proclaim to all nations of the earth the truths revealed by God, was given to the apostles by Our Lord at the time of His ascension.

Our Lord, before ascending into heaven, spoke to His apostles as follows: “All power is given to Me in heaven and in earth; going, therefore, teach ye all nations: baptizing them in the name of the Father and of the Son, and of the Holy Ghost: . . . and behold I am with you all days, even to the end of the world” (Matt. xxviii. 18-20). For this reason the apostles and their successors have never allowed themselves to be prohibited by any earthly authority from preaching the Gospel (Cf. Acts v. 29). Nor has the Church ever been turned aside from fulfilling her mission of preaching the Gospel, by the opposition of the world. Even now in many countries the State seeks to make the Church dependent on her. It is in consequence of the command given by Our Lord to the apostles, that the Popes send missionaries to the heathens, and issue Papal briefs and rescripts to Christendom; that bishops send priests throughout their dioceses, and publish pastoral letters; that parish priests instruct their people by sermons and Catechism. While the Catholic Church spreads the Word of God by means of preaching, Mahometans spread their beliefs with fire and sword, and Protestants by means of the Bible.

It is an error to suppose that Holy Scripture is the only means intended by almighty God to communicate to the nations of the earth the truths of revelation.

It was the will of God to make use of preaching for the conversion of the world. Our Lord said to His apostles, “Go and teach all nations,” not “Go and write to all nations.” Out of the apostles only two wrote; all the rest preached. The apostles themselves were the books of the faithful (St. Augustine). St. Paul tells us that “Faith cometh by hearing” (Rom. x. 17), not from mere books. Teaching by word of mouth corresponds to human needs; every one prefers to be taught, rather than to have to hunt out the truth from books by study. If writings were the only means by which men could arrive at a knowledge of revealed truth the Christians of the first two centuries would have been at a terrible disadvantage; so too would those who cannot read, as well as the great mass of mankind in the present day, who have neither the knowledge nor the capacity to penetrate the meaning of the written Word. Yet it is the will of God that “All men should come to a knowledge of the truth” (1 Tim. ii. 4). Holy Scripture soon loses its value in the eyes of those who have not the assurance of the living Word that it is truly of divine origin. St. Augustine says: “I should not believe the Gospel unless the authority of the Church moved me to do so.”

A truth which the Church puts before us as revealed by God is called a truth of faith, or a dogma.

Either a universal council (i.e., one consisting of the bishops of the whole world) acting under the authority of the Pope, or the Pope himself, has power to declare a truth to be revealed by God. Thus the Council of Nicea declared the divinity of Our Lord to be an article of faith; and Pope Pius IX. the Immaculate Conception of the holy Mother of God (1854). Thereby no new doctrines were taught, but these truths were declared to have been truly revealed by God, and thenceforth they became dogmas of the faith. When a child advances in its knowledge of religious truth, it does not really change its belief; so the Church, the collected body of all the faithful, receives dogmas new to it, when, on the appearance of some new form of error, it sets forth, after careful examination, certain truths of religion in explicit form and imposes their acceptance on all the faithful. Before the definition of it by the Church it was only a “pious opinion,” or one proximate to faith. Such is at the present time the belief in the assumption of the body of Our Lady into heaven.

2. The Catholic Church derives from Holy Scripture and from Tradition the truths that God has revealed.

Holy Scripture and Tradition are of equal authority, and claim from us equal respect. Holy Scripture is the written, Tradition the unwritten Word of God. St. Paul exhorts the faithful to hold fast the traditions they have received, whether it be by word of mouth or by writing (2 Thess. ii. 14).


1. Holy Scripture or the Bible consists of seventy-two books, which were written by men inspired by God, and under the guidance and influence of the Holy Ghost. These seventy-two books are recognized by the Church as “the Word of God.”

The Holy Ghost inspired in a very special way the writers of Holy Scripture; He moved them to write, and guided and en lightened them while they were writing (Cf. 2 Tim. iii. 16; Matt. xv. 3; Mark xii. 36). The Council of Trent and the Vatican Council have expressly declared that God is the Author (auctor) of Holy Scripture. St. Augustine says: “It is as if the Gospels were written down with Christ’s own hand.” “The writers of Holy Scripture,” says St. Laurence Justinian, “were like a musical instrument on which the Holy Spirit played.” Yet they were not mere passive instruments; each writer brings his own personal character with him into what he writes. They are like a number of painters, who all paint a building which they see in the clear daylight, quite correctly, but yet with a great many points of difference, according to their respective talent and skill. Hence it follows that there are no errors in Scripture. We must not look to the individual words, but to the general sense. We must not take offense at popular expressions which are not scientifically correct, as when the motion of the sun, sunrise, and sunset, are alluded to. Moreover, since the Bible contains the Word of God, we must treat it with great reverence. Thus the people always stand up when the Gospel is being read at Mass; oaths are taken on the book of the Gospels; in Mass the deacon approaches the book of the Gospels with incense and lights. The Council of Trent imposes special penalties on those who mock at Holy Scripture. The Jews had the greatest reverence for the Scriptures and the precepts therein contained.

The seventy-two books of Holy Scripture are divided into forty-five books of the Old Testament and twenty-seven of the New. They are moreover divided into doctrinal, historical, and prophetical books.

Old Testament.  The historical books comprise (1), The five books of Moses, which contain the early history of man, the lives of the patriarchs, and the history of the Jewish people up to the time of their entrance into the Holy Land. (2), The books of Josue and Judges, which relate their conquest of Palestine and their struggles with surrounding nations. (3), The four books of Kings, which recount their history under their kings. (4), The book of Tobias, which gives an account of the life of Tobias and his son during the captivity. (5), The books of the Machabees, which relate the oppression of the Jews under Antiochus, etc. The doctrinal books comprise the story of Job, the Psalms of David, the Proverbs of Solomon, and the books of Ecclesiastes, Wisdom, and Ecclesiasticus. The prophetical books comprise the four greater prophets, Isaias, Jeremias, Ezechiel, and Daniel, and the twelve lesser prophets, Jonas, Habacuc, etc.

New Testament.  The historical books are the four Gospels, and the Acts of the Apostles. The doctrinal books are the twenty-one Epistles, including fourteen of St. Paul’s epistles. The prophetical book is the Apocalypse of St. John, which tells in obscure language the future destinies of the Church. Most of the books of the Old Testament were originally written in Hebrew, most of the New in Greek. The Latin translation of the Bible called the Vulgate is an amended version of the translation made by St. Jerome about A.D. 400. The Vulgate is declared by the Council of Trent to be an authentic rendering of the original.

The most important books of Holy Scripture are the four Gospels and the Acts of the Apostles. The four Evangelists relate the life and teaching of Our Lord; the Acts of the Apostles recount the labors of St. Peter and St Paul.

The writers of the Four Gospels are called the four Evangelists. Two of them, St. Matthew and St. John, were apostles, St. Mark was a companion of St. Peter, and St. Luke of St. Paul on his apostolic journeys. St. Matthew’s gospel was originally written in Hebrew, for the benefit of the Jews of Palestine. He shows how Jesus of Nazareth fulfilled the prophecies of the Old Testament, and proved Himself to be the true Messias. St. Mark wrote for the Christians of Rome and shows Christ to be the Son of God. St. Luke wrote for a distinguished citizen of Rome, named Theophilus, in order to instruct him in the life and doctrine of Christ. We owe to St. Luke many details about Our Lady, and many parables not given by the other Evangelists. St. John wrote his gospel in his old age, to prove against the heretics of the time that Jesus Christ is truly God. He quotes chiefly those sayings of Christ from which His divinity is most clearly proved. The Gospels were probably written in the order in which they stand; St. Matthew wrote about A.D. 40, St. Mark and St. Luke some twenty-five years later, St. John about A.D. 90. The four Gospels were collected into one volume in the second century.

It can be proved from internal evidence that the Gospels were written by disciples of Christ, and narrate what is true. We can also prove from the oldest copies, from translations, and from quotations, that no change has been made in them since they were first written. The Gospels are therefore genuine, worthy of belief, and incorrupt.

On reading the Gospels we recognize at once that they were the work of Jews. The writers introduce Hebrew expressions (Luke viii. 14; John xvii. 12). They wrote before the destruction of Jerusalem, as we gather from their intimate acquaintance with the city. If they had written in the second century, they could not have possessed this knowledge. Their style shows that they were unlettered men. The vividness of their descriptions proves them to have witnessed the scenes and events they describe. The testimony of the most ancient Christian writers, and the consent of the churches also prove the genuineness of the Gospels. The truthfulness of the Evangelists appears in their quiet and passionless manner of writing; they do not conceal their own faults, and narrate what they knew would expose them to persecution and danger of death; they all draw the self-same picture of Christ, though writing in different places and to various readers; the apparent discrepancies disprove any sort of conspiracy among them or any copying from one another. Lastly, it would be impossible to invent such a lofty type of character as that of Jesus Christ. The Gospels have not been in any way altered in the course of time. The earliest copies and translations agree with our present Bibles, e.g., the Syrian translation (called the Peshito), which dates from the second century, and the Latin (called the Halo), which dates from A.D. 370, besides numerous copies of the original text dating from the fourth century onwards. During the first two centuries the Scriptures were read every Sunday in the various Christian churches and were most carefully guarded. We also find a mass of quotations in the early Christian writers, which prove their text to have been identical with our own. The Old Testament has always been most jealously guarded by the Jews, who in their reverence for it counted the very letters. There is, moreover, no doubt that God watched over the integrity of Holy Scripture, and would no more have allowed the early centuries alone to profit by it, than He would have created the sun for the first generations of men only.

The reading of Holy Scripture is permitted to Catholics, and is very profitable to them; but the text used by them must have been authorized by the Pope, and must be provided with explanatory notes.

In Holy Scripture we learn to know God aright; we see His omnipotence (in creation and all the wonders narrated in the Bible), His wisdom (in guidance of individuals and of the whole human race), His goodness (in the Incarnation and the sufferings of Our Lord). We have in the saints, and above all in Jesus Christ, glorious examples of virtue to incite us to the like. “The Bible,” says St. Ephrem, “is like a trumpet that inspires courage into soldiers. It is like a lighthouse, which guides us to a safe haven, as we sail over the perilous sea of life.” It also warns us against sin, shows its awful con sequences, as in the story of the Fall, of the Flood, of the cities of the plain, of Saul, Absalom, Judas, Herod, etc. It contains all that is profitable to man, and a great deal more than can be found elsewhere. It is like an overflowing well that can never be exhausted. There is always something new to be found in it. But he who desires to understand and profit by it, must have something of the spirit with which the minds of its writers were full; else he will never penetrate beneath the surface, or arrive at its true meaning.

The reason why we are not permitted to read any version of the Bible that we choose is (1), Because the unaltered text and true explanation of it are only to be found in the Catholic Church. (2), Because the greater part of it is very difficult to understand.

It is only to the Catholic Church, i.e., to the apostles and their successors, the bishops, that Our Lord has promised the gift of the Holy Spirit, and that the gates of hell shall not prevail against it. Hence the Holy Scripture, out of which the Catholic Church draws her teaching, cannot possibly be altered or corrupted. Heretics have on the other hand sometimes changed the meaning of particular passages in their own favor, or have omitted whole portions if they did not please them. Thus Luther rejected the epistle of St. James, because the apostle says that faith without works is dead. The difficulty of understanding Holy Scripture is a further reason for the Church’s restrictions. How few there are who can honestly say that they thoroughly understand the epistles that are read at Mass and these are chosen for their simple and practical character. St. Peter himself says (2 Pet. iii. 16) that in the epistles of St. Paul there are some things hard to be understood, and that the unstable would pervert these to their own destruction. St. Augustine says: “There are more things in the Bible which I cannot understand than those I can understand.” The prophetical books are specially obscure. Hence the necessity of an authentic exposition of the Bible. Heretics often give half a dozen different meanings to the same passage. The Catholic Church is the authority that God has appointed to explain Holy Scripture; for to her the Holy Spirit has been given. The child brings the nut that has been given it to its mother to be cracked; so the Catholic comes to the Church for the explanation of the Bible. This is why only Bibles with explanatory notes are allowed to Catholics.

2. The truths of divine revelation, which have not been written down in the pages of Holy Scripture, but have been transmitted by word of mouth, are called Tradition.

The apostles received from Our Lord the command to preach, not to write. Their writings are concerned more with the doings than with the teaching of Christ, hence their instructions on points of doctrine are very incomplete. They themselves say that there is much that they have delivered to the faithful by word of mouth (2 John 12; 1 Cor. xi. 2; John xxi. 25). Accordingly we are referred to Tradition. It is by Tradition that we know that Our Lord instituted seven sacraments. It is by Tradition that we are taught that there is a purgatory, that Sunday is to be kept holy, and that infants are to be baptized. It is Tradition which teaches us what books belong to Holy Scripture, etc. Tradition comes down to us from the time of the apostles. Just as those who follow up the course of a stream gradually draw near to the fountain-head, and thus discover how far the water flows, so we can search out the historical sources of the teaching of the earlier centuries of the Church, and arrive at her true doctrine. Every doctrine that has always been believed in by the universal Church, comes down to us from the apostles. If there fore there is any doctrine of the Church that we do not find in Holy Scripture, we shall find it in the stream of Tradition, and shall be able to trace it up to the first ages of Christianity.

The chief sources of Tradition are the writings of the Fathers, the decrees of Councils, and the Creeds and prayers of the Church.

The Fathers of the Church were those who were distinguished in the early ages of the Church by their great learning and holiness. Such are St. Justin, the philosopher and zealous defender of the Christian religion (A.D. 166), St. Irenseus, Bishop of Lyons (A.D. 202), St. Cyprian, Bishop of Carthage, etc. Many of these were disciples of the apostles, and are termed apostolic Fathers, as St. Ignatius, Bishop of Antioch (A.D. 107). The Doctors of the Church were those who in later times were distinguished for their learned writings and their sanctity. There are four great Greek Doctors, Saints Athanasius, Basil, Gregory, and John Chrysostom; and four Latin, Saints Ambrose, Augustine, Jerome, and Pope Gregory, called Gregory the Great. In the Middle Ages there were four other great Doctors of the Church, St. Anselm, Archbishop of Canterbury, St. Bernard, Abbot of Clairvaux, St. Thomas Aquinas, and St. Bonaventure. Among the most distinguished Doctors of later times were St. Francis of Sales, Bishop of Geneva, and St. Alphonsus Liguori. We shall speak hereafter of the decrees of Councils and of Creeds as the sources of Tradition. The prayers of the Church are to be found primarily in the Missal, but also in other books used in the administration of the sacraments and other rites of the Church. Thus we find in the Missal prayers for the dead, whence it follows that the Church teaches their efficacy.