What is Faith?

Picture a wedding. The groom stands at the altar and is asked whether he takes this woman to be his wife. He answers, “I do.” Now ask yourself: what has he just done? Has he affirmed a set of facts about her? Has he expressed confidence that she will be good to him? Or has he done something larger, pledging himself to her, promising a fidelity that will have to be lived out in ten thousand small acts over the years to come?

Most of us sense immediately that “I do” is the third thing. It contains belief and trust, but it is not exhausted by them. It is a giving of the self. And that, I want to suggest, is the closest everyday analogy we have to what the New Testament means by faith.

 

Three Proposals

Christians have long debated what faith actually is. Some have described it primarily as intellectual assent: to have faith is to hold certain truths as true. Others have emphasized what the old theologians called fiducia, or trust: faith is leaning your whole weight on the promises of God.

Both descriptions capture something real. But a third tradition has insisted on something more, speaking of “faith formed by love.” Thomas Aquinas put it starkly, teaching that charity is the very “form” of faith, the thing that gives it life (Summa Theologiae II-II, q. 4, a. 3).

Which is right? Scripture itself gives us a way to test the proposals.

 

Paul’s Test Case

In his great hymn to love, Paul writes: "And if I have prophetic powers, and understand all mysteries and all knowledge, and if I have all faith, so as to remove mountains, but do not have love, I am nothing" (1 Corinthians 13:2).

Paul imagines a faith so strong it can relocate mountains, and then declares that without love, the one who holds it is nothing. This single sentence dismantles the first two proposals when they stand alone.

If faith were merely assent to correct information, we would have to admit that the demons possess it. James says exactly this: "You believe that God is one; you do well. Even the demons believe—and shudder" (James 2:19).

Orthodox doctrine, held by a heart that hates God, saves no one.

But notice that Paul’s test also cuts against faith as mere trust. Mountain-moving faith is precisely a faith of tremendous confidence in God’s power. It leans on him hard enough to expect miracles.

Yet Paul says that even this, if it lacks love, amounts to nothing.

Trust in God’s ability is not the same as love for God himself. A person can rely on God the way one relies on a bank, without any surrender of the heart. I "trust" when I deposit my money in the bank that it will be there when I withdraw it. I am under no pretense that the banker loves me. And I certainly have no deep affection for the banker.

What remains is faith formed by love: a faith in which believing and trusting are gathered up into a living bond of devotion. Paul says as much elsewhere: "the only thing that counts is faith working through love" (Galatians 5:6).

 

A Word with Deep Roots

The Greek word the New Testament uses, pistis, did not fall from the sky.

The apostles inherited it from the Septuagint, the Greek translation of the Hebrew Scriptures, where it regularly renders the Hebrew emunah. And emunah does not primarily mean “belief.”

It means steadfastness, reliability, fidelity.

Consider Exodus 17, where Moses holds up his hands during Israel’s battle with Amalek. The text says his hands remained “steady” until sunset. The word is emunah. Faith, in its Hebrew roots, is a hand that does not drop, a loyalty that holds its position.

The prophet Habakkuk gives us the verse Paul will later make central: "Look at the proud! Their spirit is not right in them, but the righteous live by their faith" (Habakkuk 2:4).

In context, this is not about holding right opinions; it is about remaining faithful to God while the world collapses. The Septuagint even renders it “the righteous shall live by my faithfulness,” highlighting that God’s fidelity and ours meet in this one word.

In ordinary Greek, too, pistis frequently meant loyalty or allegiance, the fidelity owed to a king or a friend. When Paul speaks of "the obedience of faith" (Romans 1:5), he is not stringing together two unrelated ideas.

Faith is a form of obedience, an allegiance to Jesus as Lord. Even our English word “faith” preserves the memory: it comes from the Latin fides, from which we also get “fidelity.”

 

The Dichotomy Dissolves

Once faith is understood this way, a famous tension in Scripture quietly resolves itself. Paul insists we are justified by faith and not by works. James insists that "faith without works is also dead" (James 2:26).

For centuries these texts have been pitted against each other.

We've ended up in a battle of verses versus verses.  Some of us citing passages that emphasize faith, others that emphasize obedience and works.  Then, we end up trying to come up with really difficult explanations of the other person's verses to make them fit.

But if faith is allegiance formed by love, then works are not something added to faith from outside, like a tip added to a bill.

It fits all the verses without any need to try and "explain away" some of them.

Such deeds/works/acts of obedience are faith’s own body.

A husband’s daily kindnesses are not payments he makes to earn his marriage; they are what his “I do” looks like when it is lived out in the years and decades after the vow.

Paul rejects works performed as credentials, as though we could present God with an invoice.

James rejects a “faith” that is a corpse, all creed and no heartbeat.

They are describing the same reality from two sides. Paul himself shows the unity when he writes that he lives "by faith in the Son of God, who loved me and gave himself for m"” (Galatians 2:20).

Faith here is a response of love to a love already given.

 

Living It

First, stop measuring your faith by the intensity of your feelings or the degree of your doubts. Measure it by fidelity. Did you show up to prayer when it was dry? Did you keep your word to God when no one was watching? This does not mean you will not have moments of imperfection. A husband and wife sometimes have struggles, even a few fights. They let each other down. But that's not the same thing as infidelity. One kind of imperfection is something they work through, and grow through together. The other threatens to foundation of the marriage. '

Second, treat every act of love as an act of faith. When you forgive someone, feed someone, or hold your tongue for someone, you are not doing something in addition to believing. You are believing with your entire self. Not just an act of the mind, but an act of you.

Third, in seasons of darkness, when God feels absent and doctrines cause a headache, remember Moses’ arms at sunset. Faith in the dark is simply not letting go. You may not feel trust; you may not feel certainty. But you can still say, quietly and again, “I do.”

That is faith. And it is formed by love.