“Faith” from Back to Virtue by Peter Kreeft (pg.72-73)

"Faith is first. But what is it? It is not mere belief, or mere trust, though it includes both. Belief is an intellectual matter (I believe the sun will shine tomorrow; I believe I am in good health; I believe the textbooks). Trust is an emotional matter (I trust my psychiatrist, or my surgeon, or my architect). Faith is more. It flows from the heart, the center of the person, the prefunctional root out of which both the intellectual and the emotional branches grow. Faith is the yea-saying of the I, the commitment of the person. 

The object of faith is God, not ideas about God. It is essential to know things about God, but it is more essential to know God. Saint Thomas Aquinas, that most rational (not the same as rationalistic) of theologians, insists that ‘the primary object of the act of faith is not a proposition but a reality’, God himself…. The creedal truths about him are a description of faith, a defining, a statement of structure. The creeds are like accounting books, God is like the actual money. 

Though the root of faith is not intellectual, its fruit is. ‘Faith seeing understanding’, fides quarens intellectum - this was the operative slogan for a thousand years of Christian philosophy. ‘Unless you believe, you will not understand’ - faith first. But ‘in they light we see light’ - understanding follows. How accurately the saints knew God; how mistaken all the unbelieving geniuses were!

Faith is more active than reason. Faith runs ahead of reason. Reason reports, like a camera. Faith takes a stand, like an army. Faith is saying Yes to God’s marriage proposal. Faith is extremely simple. Saying anything ore would probably confuse it. Most of what is written about faith is needlessly complex. The word yes is the simplest word there is. "