Insufficiency of Reason and the Necessity of Faith
The insufficiency of reason is proved thus; man owes homage to God for all that he has received from Him. Man has received from Him all he is and all he has and thus owes himself entirely to God. Man has received an intelligence capable of knowing the truth, which constantly longs after the truth, yet is too limited to know and comprehend all truth and easily takes error for truth. In him exists ignorance of many things, even in the realm of nature, the need to be enlightened upon that of which he is ignorant, or he does not understand, the necessity to be taught if he wishes to be enlightened, and the need to listen to those wiser than himself.
God alone possesses infinite knowledge of all things, knows and comprehends all possible truths, is of all truths the most profound and the most wonderful, has reserved to Himself the imparting of the knowledge of the mysteries He judges best to reveal to man, is the Truth itself, a Shelter from all error, and has every right to be believed on His Word whatever He judges best to reveal of Himself and His will.
Hence it follows that, first, mysteries are not only probable, but also inevitable for man, in the material universe and much more in things immaterial and spiritual; second, religion in general, and any prescribed religion whatever cannot be truly divine, but on the condition that it teaches mysteries; third, a religion that has no mysteries, is by that alone convicted of being but a human invention; fourth, man should submit his limited intelligence to the infinite intelligence of God, as soon as it is proved to him that such or such a mystery is revealed by God, even though he does not comprehend it.
Thus, to submit one's reason to God is to have trust in God, to render homage to the infinite intelligence of God, and to fulfill one's first duty to Him.
The Agreement of Faith with Reason
The fact of revelation is possible because it never exceeds the omnipotence of God. It is expedient because nothing is more natural than the conversation between a father and his children, instructing them in useful or necessary things. It is necessary because, chiefly, without this help, man could not have arrived at a knowledge of truths pertaining to his destiny and because, after having known them, he allowed them to become obscured by idolatries.
First, it was given in a limited degree to our earliest ancestors, God speaking through nature and conscience, and in other ways. Second, to the Hebrew people, through the ministry of Moses and the prophets, to preserve and develop the primitive revelation. Third, to the entire world by Jesus Christ, to perfect the design of the preceding revelations and make known the full counsel of God respecting man's redemption and elevation to glory.
Our confidence in it rests upon the necessity of revelation, the traditions of all ancient people, the unanimous faith of Israelites and Christians, and upon monuments and wonders, which surround us as living witnesses today.
God, first, has allowed the human mind full exercise of its natural powers in accomplishing it. Second, He has never humiliated it. Third, He has only supplemented man's natural powers in reference to supernatural truths. Fourth, He has ennobled and elevated man in opening to him the world of the supernatural. Fifth, He has done an act of goodness and benevolence to man. Therefore, nothing is more favorable to reason than revelation. Nothing is more conformable to reason than submission to its teaching. Nothing is in better accord than faith and reason.
The truths of this revelation are contained in four sources, summarized in the Apostles' and Nicene Creed:
It is contained in the Holy books of the Old and New Testaments.
It is contained in the decisions of the Seven Ecumenical Councils.
It is contained in the common consent of the Catholic Church.
It is contained in the Apostolic Traditions preserved by the Fathers.
To reject revelation is to go against reason, to put aside Christ and His Church, to put one's intelligence above God, to refuse Him the homage of reason, and to deny the eternal veracity of God.