Aquinas on the Necessity of Revelation

Excerpt

It was necessary for man’s salvation that there should be a knowledge revealed God, besides philosophical science built up by human reason. Firstly, indeed, because man is directed to God, as to an end that surpasses the grasp of his reason: The eye hath not seen, O God, besides Thee, what things Thou hast prepared for them that wait for Thee (Isa. 66:4). But the end must first be known by men who are to direct their thoughts and actions to the end. Hence it was necessary for the salvation of man that certain truths which exceed human reason should be made known to him by divine revelation. Even as regards those truths about God which human reason could have discovered. It was necessary that a man should be taught by a divine revelation; because the truth about God such as reason could discover, would only be known by a few, and that after a long time, and with the admixture of many errors. Whereas man’s whole salvation, which is in God,  depends on upon the knowledge of this truth. More

Thomas Aquinas. Summa Theologica. Trans. Fathers of the English Dominican Province. London: Burns Oates & Washbourne. Print.