The philosophy of Aquinas has exerted enormous influence on subsequent Christian theology, especially that of the Roman Catholic Church, extending to Western philosophy in general, where he stands as a vehicle and modifier of Aristotelianism, which he fused with the thought of Augustine.
Aquinas believed “that for the knowledge of any truth whatsoever man needs Divine help, that the intellect may be moved by God to its act.” However, he believed that human beings have the natural capacity to know many things without special divine revelation, even though such revelation occurs from time to time, “especially in regard to [topics of] faith.” Aquinas was also an Aristotelian and an empiricist. He substantially influenced these two streams of Western thought.
Aquinas believed that truth is known through reason (natural revelation) and faith (supernatural revelation). Supernatural revelation is revealed through the prophets, Holy Scripture, and the Magisterium, the sum of which is called “Tradition”. Natural revelation is the truth available to all people through their human nature; certain truths all men can attain from correct human reasoning. For example, he felt this applied to rational proofs for the existence of God.
Though one may deduce the existence of God and His Attributes (One, Truth, Good, Power, Knowledge) through reason, certain specifics may be known only through special revelation (Like the Trinity). In Aquinas’s view, special revelation is equivalent to the revelation of God in Jesus Christ. The major theological components of Christianity, such as the Trinity and the Incarnation, are revealed in the teachings of the Catholic Church and the Scriptures and may not otherwise be deduced.
Supernatural revelation (faith) and natural revelation (reason) are complementary rather than contradictory in nature, for they pertain to the same unity: truth.
Here to expound further are the ladies of The View (stuck somewhere in the Middle Ages) :