Faith is a very tricky concept to understand, because from the beginning of Christianity, it has meant more than one simple thing. Clearly, there is an intellectual manner of faith, as when we believe the content of what Jesus revealed. However, if you look closely at the Christian tradition as well as the early texts of the New Testament, you will find that the term “faith” is used in a broader way than just intellectual assent. It’s not as clear to English readers sometimes because we tend to distinguish “faith” from “belief.” We sometimes speak of believing that something is true as opposed to having faith in someone. Notice the difference in the prepositions “that” and “in.” When we interpret faith solely as an intellectual act, i.e., as believing that something is true, it appears that we are leaving something out, the “having faith in” sort of faith.
Academic belief, knowing all that the catechism teaches and saying, “Yes, I believe that,” is insufficient for the full commitment of our lives that Jesus demands.
In the Greek of the New Testament, we find no difference in the noun we translate as “faith” and the verb we translate as “believe.” Pistis is the Greek word for Faith, and pisteuo is the Greek word for Believe. You can see that the two words share exactly the same root in Greek whereas they don’t in English. As a result, when the early Christians talked about faith, they bundled up a whole lot more than just “believing that.” Sometimes the concept of faith/belief means just that, believing that something that God has revealed is true. But other times the concept of faith/belief means loyalty, allegiance, and keeping faith with someone. And sometimes the concept of faith/belief means trusting a person without a specific objective or belief in mind at all!
To help us get at these differences in English, our prepositions really assist us. Think about how differently it is to say, “I believe you” vs. “I believe in you.” If I say, “I believe you,” it means that I am agreeing that something you have just told me is true. If I say, “I believe in you,” it likely means that I am agreeing with something you have told me, but it also means much more, such that I am likely to believe other things that you will tell me. And, even more interestingly, it can mean that I trust not only your future intellectual judgment, but your practical judgment, i.e., I believe in you in the sense that I trust that you will live up to your potential, that you will fulfill your life, and, reciprocally, that you will act in ways that are good for me (and not harm me). It is this last sense of Faith that is especially practical and far less intellectual that I am aiming at here, because I am convinced that the Biblical writers often have this in mind when they talk about pistis/pisteuo that we translate as faith and believing.
In fact, the Greek of the New Testament makes extensive use of prepositions, just as we do in English, and these can help us more fully understand what they meant by “faith.” Consider these three New Testament phrases:
“Believe, and thou shalt be saved.”
“Believe in the Lord Jesus Christ.”
“Believe on the Lord Jesus Christ.”
Notice that in the first case, the belief/faith seems to be intellectual, believing that something is true. In the second case the preposition “in” suggests belief/faith of the trusting sort mentioned at the end of the previous full paragraph. In the last case we find a locution that is curiously absent from our contemporary English speech. Nobody talks about believing on other people. At best we would interpret that metaphorically, so that if we believe on someone, it means that we feel that the person or what he says can function foundationally for us. Thus, if you believe on the Lord, then you place your life, your future, your hopes on him, a concept that resonates with religious commitment.
If you believe "on" the Lord, then you place your life, your future, your hopes on him, a concept that resonates with religious commitment.
To help us more fully grasp the difference between intellectual faith and practical faith, let’s consider the use of these terms applied to equals. Suppose I say to my wife (an equal), “I believe in you.” Without any specific context, it doesn’t mean that I believe a particular thing she is advocating. With a context, it does. So, if my wife told me she saw a ghost, and I say, “I believe in you,” I’m telling her two things. First, I believe that what she told me is something true, namely that she really saw a ghost. Second, I in general trust what she tells me, even if it’s not something that I saw for myself, and even if, let’s say, I’m not the sort that would have believed in ghosts before. Without a context, my saying in general, “I believe in you,” is more along the lines of what a coach tells us before the game. It’s less about agreeing with what she says, and more about expressing confidence in how she is going to perform. Accordingly, it is practical, a practical expression of faith in a person.
Let’s turn now to practical faith in people who are unequal to us, because this is where the situation gets really interesting. Suppose a politician declares, “Believe in me, and I will better the country.” He is asking for our vote to trust him to do something, a case of practical faith. But that something is pretty broad, not just one or two items in the political platform. When we vote for a governor or a president, we are trusting or hoping that the person will make the right sorts of decisions in situations that neither we nor they can predict. We believe in them. This is a belief in someone greater than ourselves, and so, we would use terms like allegiance or loyalty to describe it.
Let’s up the ante a final time and imagine the greatest possible inequality, namely that between God and us. What does God mean when he asks us to believe in him? Well, many people say, “I believe in God.” They mean at least that they think that God exists, the sort of intellectual faith we described before, believing that. But it means at least a little bit more than that in contemporary America, some vague sense that somehow because God exists, things will more or less ultimately work out in the end. Notice how that couples an intellectual belief/faith with a practical belief/faith, for the person trusts God in a case that goes beyond any specific circumstance.
It is this total allegiance faith—believing that, plus believing in, plus believing in the infinite God—that is salvific.
But I asked in the last paragraph not just what we mean in 21st century America when we offhandedly say, “I believe in God,” but what God meant in the first century when his Son said, “Believe in me.” Because of the extreme inequality between God and man, the sort of faith Jesus is asking for is infinitely beyond what we would or should maximally offer to a politician. Jesus is asking us for our total trust in him, that what he says is true, yes, but also that what he does will work out for the best, even when we cannot see what that “best” is or how it will be achieved. This sort of faith is that total allegiance sort, the “keeping faith,” that the New Testament writers are after when they talk about believing until the bitter end. It is this total allegiance faith—believing that, plus believing in, plus believing in the infinite God—that is salvific. For when we express total allegiance faith, each of our faculties, not just our intellects, are directed toward God in trust, a trust that in our desires and imaginations effects hope and in our wills effects love. This is why we say that faith produces hope produces love.
When we express total allegiance faith, each of our faculties, not just our intellects, are directed toward God in trust, a trust that in our desires and imaginations effects hope and in our wills effects love.
So, when you hear the New Testament writers speak of walking by faith not by sight, it is this total allegiance kind of practical faith that they mean. They never mean living irrationally or foolishly in opposition to wisdom. Why? Because the intellectual virtue of faith completes wisdom. Instead, they mean that our intellects rarely can grasp the full picture of what God is really up to, but we still must keep on choosing to believe him, to believe in him, and to remain loyally fixed in our confidence and hope in him. Thus, intellectual faith is never enough. Academic belief, knowing all that the catechism teaches and saying, “Yes, I believe that,” is insufficient for the full commitment of our lives that Jesus demands. There is an act of the will that moves beyond belief, that moves to the practice of trust in a complete allegiance to a King and God. This is what Jesus demands of us when he tells us, "No one, after putting his hand to the plow and looking back, is fit for the kingdom of God." Luke 9:62 NASB.