Aquinas in "Politics and Ethics"

Aquinas said "If it were left solely to reason to seek the truth about God, few men would possess a knowledge of God." (Ch. 4, p. 4) Because true understanding of God can only be obtained with a level of knowledge un-possessed by the common man, the Church has been created to facilitate reason for man. This is done so that man can have faith in God. The achievement of faith requires one to have strong reason …

…and desires is to know the first truth; namely, God." (Ch. 25, p. 7) Although it is considered acceptable for most believers to use reason to justify existing faith, they believe that reason isn't necessary to have faith, and that the most valid form of faith requires no reasoning at all. The achievement of faith requires one to have strong reason to possess a firm foundation in the Church of God. Outside Source: NewAdvent.org; Summa Theology