There seem to be two main ways of understanding what faith is today.
On the one hand, faith is seen as a personal trust in Jesus Christ. On the other hand, faith is seen as a form of knowledge—a firm belief in certain things like the resurrection of the dead or the necessity of baptism such that faith becomes a kind of knowledge.
For those of us who like to think about our faith and understand it better there seems to be a potential confusion here that should be cleared away. Much of it stems from historical circumstances. Martin Luther, in his break away from the Church, threw heavy emphasis on faith as personal trust. Luther expected faith to do the work of what Catholics properly understand as the virtues of hope and love. For Luther it was all faith—a dangerous conflation of the theological virtues that became one of the fatal flaws of the Reformation.
On the Catholic side, the Thomistic definition of faith seems to pull in the opposition direction, with a heavy accent on faith as knowledge. Faith here is defined as the act of the intellect assenting to a Divine truth owing to the movement of the will, which is itself moved by the grace of God. That remained the classic definition of faith for centuries, and is how the Catholic Encyclopedia defined it at the turn of the last century. (The wording above is theirs.) But since the Second Vatican Council, it has become much more common among Catholics to speak of faith in terms of our relationship with Christ.
Some verses seem to support a more intellectual view of faith itself. Perhaps most famous of these is James 2:19, “You believe that God is one. You do well. Even the demons believe that and tremble.” On the other hand, there are verses like the classic John 3:16, “For God so loved the world that he gave his only Son, so that everyone who believes in him might not perish but might have eternal life.” (And yes, the verb to believe is the same in the Greek for both. It’s pisteuó, pronounced, pist-yoo’-o.)
So which is it? Is faith personal trust or intellectual assent to divinely revealed truth?
The answer, importantly, seems to be both.
First, let’s make some key clarifications. To whatever extent we as Catholic Christians can affirm faith as personal trust, in no way does that mean we accept Luther’s swollen conception of faith as somehow how having swallowed up the two other theological virtues. The Lutheran distortion of this must be rejected.
Second, even with a more intellectual conception, the obvious needs to be stated: our faith is in a person above all else, not an idea, a principle, or a thing. We believe in a personal God who revealed Himself most fully in a person, Jesus Christ. By the same taken, this means that we also believe the things He teaches us. So faith does—must—include assenting to a certain set of propositions, beginning with those in the creed about baptism and eternal life. So even if we emphasize the personal aspect, it unavoidably entails the intellect.
But we still must answer our big question: How can faith be both knowledge and yet also trust?
We find our solution right where the problem seemed to begin. A quick reading of the classic Catholic definition of faith makes it seem all about the mind. And Aquinas indeed does define it as an act of the intellect. But let’s read it more closely and carefully: faith is the act of the intellect assenting to a Divine truth owing to the movement of the will, which is itself moved by the grace of God. (The full context in the Summa is here.)
First, it is important to note that right there we have a personal process at work. In that definition it is God who is at work within us through His grace. And, second, grace moves the free will which itself moves the intellect to its act of assent. So faith, while an act of the intellect, also involves the will in this way.
This means, furthermore, that faith has a special relationship with hope. In a sense, faith is to the intellect what hope is to the will. Faith is belief in the unseen, as 2 Corinthians 5:7 reminds us. In the realm of the will, the accompanying virtue would then be hope. For, as Aquinas puts it, “Now one hopes not for what one has already, but for what one has not.”
This close relationship is reflected in the classic formulation of Hebrews 11:1, “Now faith is the substance of things to be hoped for.” As Aquinas interprets it, this means that faith “contains virtually all things to be hoped for.” Or put another way, through faith we come to know that Jesus is our Lord and Savior and that we are destined for eternal happiness. We then also begin to hope for these things. But first we must ‘know’ about these things. Otherwise, how could we hope for them? (Which is the point Aquinas makes above.)
Faith is also the substance of hope not only in the sense that it contains the content of our hope. Understanding faith as knowledge also means that such hope has a firm foundation on which to base itself. For hope without faith would seem to be actually very weak, almost hopeless, actually. If I am lost at sea and I have never heard of the Coast Guard yet I still hope for rescue we might say my hope is very much an empty one. But if I have heard of the Coast Guard, then there is a reasonable basis—or, we might say, some ‘substance’—to my hope.
This is why it’s so important that we retain the classic understanding of faith as knowledge.
This definition reminds us that faith concerns objective truths that we can believe with the certitude of knowledge and that this confident knowledge is what bolsters our hope. If we discard this definition, our understanding of faith risks becoming too subjective.
Of course, we don’t want to highlight the relationship of faith to objective truth so much so that we forget about the subjective or personal element. The classic definition avoids this pitfall by incorporating an element of personal trust but in its proper measure—in recognizing that it is the will moving the intellect and that the will is in, turn, moved by God.
Because of this ‘relationship’ with the will, faith also works with and through love, the other theological virtue, which, in addition to hope, is associated with the will.
In a sense, the relationship is patterned after the one between faith and hope. Just as we need faith in order to properly hope, so also faith comes ‘first’ in a sense in that we need an initial act of faith in order to ‘know’ what to love. In the words of Aquinas, “Some act of the will is required before faith, but not an act of the will quickened by charity. This latter act presupposes faith, because the will cannot tend to God with perfect love, unless the intellect possesses right faith about Him” (See Article 7, Reply to Objection 5.)
But then faith, in turn, is ‘quickened’ by love—which is to say that faith grows strong in love. “Charity is compared to the foundation or root in so far as all other virtues draw their sustenance and nourishment therefrom,” Aquinas writes.
In more formal terms: Aquinas says love forms and perfects faith. By ‘forming’ faith charity directs it to its end, which is union with God. (Understand ‘perfect’ here to mean perfect in the sense of making something whole and complete.)
We’ve now come a long way from our main question. Let’s briefly recap: Faith is an act of the intellect assenting to divine truth. But this act of assent is moved by the will, itself gently nudged forward by the transformative grace of God. So there is an element of personal trust built into the traditional conception of faith as an act of the intellect.
Take away the intellectual aspect, however, and faith loses its objectivity as firm knowledge. This would, in turn, affect hope and love. Like musical notes, faith, hope, and love must be understood as distinct in order to see how they work so closely in concert in with each other to produce this wonderful symphony of the soul that we call salvation.